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Back to Guest Editor Columns Archives

George Irwin is our Green Wall Editor (2008) and writes "The Green Walls Column." George Irwin is the Founder of Green Living™ Technologies International (GLTi),  based in NY.  He is also the owner of the patented Green Living Walls, Green Living Roofs and is a global pioneer in Vertical Agriculture.  A published author, and featured as the “Green Wall Editor” within the industry, George is also a leading resource and authority for green wall and roof technologies around the world. TIME, National Geographic, Fortune Magazine, Profit Mag., CNN, NBC, Good Morning America and Newsweek are among the major media recognizing his efforts and the development of vertical agriculture.

George lives in Rochester, New York with his wife, son and daughter.  In his spare time he is still an avid gardener he also enjoys travel and lecturing.
email: george (at)
View George's Profile

The Green Walls Column

Hydroponic Living Walls – Irrigation
By George Irwin, The Green Wall Editor
June 18, 2013
All Photos by George Irwin Unless Otherwise Noted

Lately the requests for information about setting up irrigation for hydroponic walls have flooded my email.  Over the past 5 years I have seen more green wall companies popping up all fighting for a small piece of an infant market.  More companies equate to more inexperience, some media based, some hydroponics.

If you haven’t read my archived “Hydroponic Living Walls – DYI – Really?” you should start there to understand the dynamics of media-less horticulture and hydroponic living walls.  Because of the popularity and frankly the ease of hanging felt, foam, coco husk or scrub pads this type of living wall has gained momentum.  I can’t blame anyone for wanting to utilize this technique - it’s quite easy to install, lightweight and easy to transport but keeping the plants alive is another task.  Even with media based wall systems it is critical to have the correct lighting, moisture and nutritional needs.

Over my experience the single most important factor with hydroponic walls beyond light and nutrition is the need for oxygen exchange at the root level.  If you have already read the archived article you will know that this is the single most critical variable to prevent disease.  This is where the majority of hydroponic walls fail, plant loss due to anaerobic activity, and it is primarily due to the material used as the hydroponic build up; this is coupled with poorly devised irrigation systems and inexperience with fertilizers, nutrition and micro organisms.

Banyan Street Manor Vertical Gardens (& Rooftop Farm) in Honolulu, Hawaii; Photo Courtesy of Greg Lee.

The layers of materials literally suffocate the roots.  I equate the situation to being able to build a computer but not having the software to make it run.  In previous articles I have talked about the materials, coincidentally we have some of the newest technology being released in the next few weeks that prevents root rot and increases aerobic activity and nutrient uptake by 300%.

With our current experience we are able to utilize our patented technology with both media and hydroponic applications because there are no layers to suffocate the roots - accept my apology in advance: because of the competition I’m not going to reveal what we use in our hydro walls, however, you can enjoy the great work of Greg Lee via 1st Look Exteriors (see above) who has mastered the use of our technology specific for hydroponic use.  Yet the principles of irrigating hydroponic living walls is relatively the same.

Irrigation is the delivery of water and nutrients to the plant roots and one of the key components to hydroponic living walls.  Start with the visuals and dynamics of a hydroponic living wall realizing that, unlike horizontal growing, we have to consider the vertical alignment and gravity.

Because of gravity the calculation of water is somewhat of a guessing game for the novice.  Gravity will pull water through the wall to the bottom; this result is a system that will dry out at the top long before the bottom becomes dry with a tendency to overwater.

The best advice without disclosing the calculations is to utilize multiple zones; the more zones the more control you have over the water volume and frequency.

Ebb and Flow Kit - Top: Tray with grow blocks or pots
Bottom: Reservoir, Fertilizer and Pump - via The Green Thumb

Typical horizontal hydroponics are designed as an ebb and flow system, referencing the relation to the rhythm of the tidal changes, and require a tray.  The tray is segmented and elevates the grow blocks or containers so they are not sitting in water, and utilize a reservoir and a pump.  The tray design is important; you can’t use just any tray.  The bottom of the tray has to have raised areas to keep the roots from being submerged or sitting in water.

Hydroponic tray shown with channels that allows water and nutrients to flood the tray and recede back to the reservoir. The plant roots literally sit up and out of the water that is left in the tray preventing root rot due to anaerobic activity. 

This is exactly the same principle with the popular built up hydroponic walls!  No aerobic activity equals disease and root rot.  Typically, the pump is on a timer moving water to flood the tray with fertilizer directly to the plant root zone and then through an overflow the water drains back into the reservoir for re use.  A hydroponic living wall will not require a tray.  This is an important part to the success of a hydroponic living wall.

There needs to be aerobic activity at the root level since the layers of material sandwich the plant roots creating an anaerobic environment.  In a horizontal set up the tray allows for air flow and the roots can breathe - never being submerged in water for more than a few seconds taking up nutrients as the water recedes back to the reservoir.

Typical Ebb and Flow Cycle for Horizontal Hydroponic Applications


The above diagrams show the water flow cycle flooding the root area with nutrients and then receding back to the reservoir.  This action alone adds oxygen to the water and avoids sitting water.  An additional air stone may also be required in the reservoir to oxygenate the water.

When water is not oxygenated disease is imminent; root rot is caused by Phytophthora.  Spores will also contaminate other plants if there is adequate water.  The photo at left displays classic root rot (top plant) and the onset of the disease is shown in the lower plant.  The roots sandwiched between two wet surfaces never receive a reprieve from the constant moisture.

Living walls pose a challenge to meet a fine line and balance between having enough moisture without being excessive, causing root rot.

Looking at various types of hydroponic living walls, one uses the felt or layered type materials like the one Patrick Blanc made famous with his "Le Mur Végétal" or the Vertical Garden, and modular systems using various rooting materials from rock wool to coco husk.


Juvia Restaurant, Miami, Florida; Photo Courtesy of Patrick Blanc.

I started this article to describe the how-to process of irrigating hydroponic living walls, and as you can see just by the types of materials, there will be just as many irrigation configurations -  not to mention the new living wall technology application coming soon that will pretty much do away with 99% of water all together as if the industry is not confused enough already.

Figures 1 & 3 below display a felt layered hydroponic living wall while Figure 2 shows a bagged system with coco husk.  Both materials will require an irrigation system that is different and specific to the application of the system and the materials used.  The felt in Fig. 1 will always be wet or if it is allowed to dry out - the fabric will shed water instead of absorb it.

Left: Figure 1; Right: Figure 2

Figure 3.  This shows how overwatering a felt system can be susceptible to many problems.

The coco husk shown in Figure 2 holds no water and in fact allows 99% of the water to simply run through.  These are two extremes where clearly one system will have too much water and the second not enough making the irrigation system difficult to design around.  Also, with the felt there will always be more water at the lower portion of the wall making the calculation of the water use very difficult.  The result may be too much water, not enough water and an imbalance of nutrients.

Unlike the ebb and flow there is no rhythm to the flow of water and nutrients and no constant measurement; this also makes it difficult to monitor nutrient use and may cause over or under fertilizing.  It’s also not uncommon to include a highly technical monitoring system to alarm the technician of changes in pH, moisture levels, temperatures, nutrition, quantity and frequency or the water application.

The best advice I have for the novice living wall technician is to simply monitor the wall and collect data on a weekly basis to determine the rates and applications of water and nutrients throughout the first year.  Even if the living wall is indoors the plants will go through some seasonal changes.  Throughout the yearly cycle the technician must be acute enough to adjust the irrigation as needed.  After the first year the data log will reveal a predicted cycle.

Which irrigation system do I use for my living wall?

There are two common options.  There is a potable water connection or a reservoir.  The reservoir is typical of the ebb and flow hydroponic system with fertilizer already mixed into the water which is continuously reused until one or more of the variables such as temperature, pH, aeration, disease, etc., are altered forcing the disposal and cleansing of the holding tank. The potable water source is a direct connection to a city or water supply not recycled and will have a fertilizer injector.  This type of connection removes many of the variables in hydroponics, however, is subject to water purification additives like fluoride and chlorine.

Too many parts per million of chlorine will hinder plant growth and kill off beneficial bacteria.  To improve the quality of water it is simply a matter of adding a specialized filter to turn potable water into distilled removing the harmful additives.  Both types of irrigation systems will require specialized equipment, fertilizer, and beneficial bacteria (for example, GLTi has bioSoil).

The question you have to ask yourself is: Do I want a reservoir or do I want to use a potable water source?  Once you have decided on what the source of irrigation water will be, the next step is to calculate how many zones and in what configuration the wall will need.  I have been glad to explain how to connect from the water source to the drip lines, but how you configure the drip line is up to you.  Frankly, this is one of our trade secrets and I’m not willing to disclose the exact how-to part.

1. Point of Connection (POC)
2. Zone Valve with Filter
3. Fertilizer Injection
4. Automated Timer

We have already discussed that all irrigation systems start with the water source or supply also known as the POC or point of connection.  An ebb and flow system will contain a water reservoir with fertilizer already premixed.  The second option is to connect directly to potable water.  Irrigation is relatively simple process - the water moves through a supply line from the POC into a fertilizer source through a valve and filters and then to the specified watering “zone” controlled by the “zone valves.”  The zone is a defined area of the wall in which water is applied.  The number of zones is dependent on the size of the wall.  Depending on the location of the zone the frequency and quantity of the water is controlled by a timer, monitoring system or both.

This photo depicts the reservoir used to irrigate this living wall. This is the “Source” for this irrigation system.

Here is the critical part of experience.  Rhetorically speaking, how do I know how many zones and how much water should I calculate?  This is where I stop; sorry, irrigation is one of the critical components to the success of living walls.  But I will elaborate enough to help you experiment.

There are key variables that impact each and every living wall.  Elevation (north, south, east, or west-facing), geographic location, seasonal changes, impacting surroundings (other buildings or trees), interior applications, height, length, plant type….just to name a few!  The one piece of advice I will disclose is to use like-minded plants.  This means to use plants in the application that require the same type of water needs; this will make calculating the irrigation much easier, and you won’t have to try and decipher multiple zones and various plant requirements.

Second, remember that gravity is a part of the living wall irrigation design.  I have seen inexperienced designers and manufacturers unable to properly design irrigation systems for living walls.  Water flows down; this means the calculations for water needs based on the multiple variables have to account for the fact that the upper part of the wall will dry out faster than at the bottom.

Two additional pieces of advice: Put plants that like more water at the bottom and calculate the water volume for two different cycles, one that will saturate the entire wall and the second that will supply only the upper portion.

Remember, there are two types of applications for hydroponic irrigation.  One has a reservoir and the other uses potable water.  Both will require a fertilizer source, and both should include a biological additive like bioSoil.  The decision is simply based on preference.  The success comes from the ability to adjust the system as needed to meet the plants' needs -  according to many variables.

The Golisano Institute for Sustainability (GIS) Green Wall in Rochester, New York: Photo Courtesy of GLTi.

George Irwin, The Green Wall Editor

Hydroponic Living Walls – DIY – Really?

By George Irwin, The Green Wall Editor
February 10, 2012

Over the years I haven’t done a particularly good job writing about hydroponic based technology, more specifically hydroponic green walls.  I would contribute that to the fact that beyond the work of the ever popular Patrick Blanc, the technology was still being developed for vertical walls.

I personally have found them a cumbersome maintenance project; however there have been advances in materials and easy applications, but not without a “fine line” between success and failure.  I’m going to share some of my experiences and explain that “fine line” that includes some detailed variables.

One of Patrick Blanc's latest works in Berlin, Germany
at the Düssman das KulturKaufhaus, 2011.

Like green walls in general, hydroponic techniques are not new; the Greek term “Hydro” means water and “Ponos” is labor.  Even the gardens of Babylon had a pumping system to bring water to the top of the garden, letting it trickle back down to the lower pools.

Nature irrigates naturally occurring walls through runoff that collects nutrients from natural decomposition to feed the plants clinging to the sides of cliffs and other rock walls.  In a previous article (The Original Green Living Wall: Basis for Great Design, September 26, 2010), I described the origin of green walls and the natural rock faces created by Mother Nature. Nutrients and minerals are created naturally, picked up by runoff as the roots are bathed in a nutrient rich solution.  Sounds simple to recreate, right?  Not so fast!  We’re talking about Mother Nature here.

I have documented and studied naturally occurring green walls over the years.  Since I live in upstate New York (USA), I am much more familiar with the local native plant types except for my time spent outside of Portland, Oregon hiking to Multnomah, Latourell, Wahkeena and Horsetail waterfalls along the Columbia River.

The walls I have studied here are the epitome of “Native Living Walls.”

Living wall by Mother Nature along the Larch Mountain trail OR, consisting of  native plants including various lichen & ferns.

Before I continue let me make reference to the nomenclature of “Green Walls” as a general term, which is divided into “Green Facades” and “Living Walls.”  Since living walls are defined by having the root system throughout the wall, naturally occurring green walls are defined as living walls.

A green façade is usually a 3d trellis like support structure with a climbing plant found at the base.  In nature climbing plants are also naturally occurring however for the purpose of this article our focus is living walls.

Although my hiking has decreased to almost none over the past year due to knee surgeries, I still feel that naturally occurring living walls provide a spectacle only found in nature.  Plants we see as common or to the untrained eye might seem like nothing more than moss and ferns.  A close look displays an awesome range of colors and textures; to the touch on a hot summer day the walls are cooling and provide a haven for animals and insects of all kinds.  Every wall I have seen up-close has contained a variety of liverworts, ferns, mushrooms, lichens and wild flowers.

Left to Right:
Anomodon attenuatus (anomodon moss),
Atrichum undulatum (undulate atrichum moss).

Left to Right:
Dicranum fulvum (dicranum moss), Asplenium scolopendrium (Hart's-tongue fern) -  this fern is on the New York State Threatened List and the majority of these can be found in New York State.

The pictures provide just a small sample of what can be found growing on the natural living walls.  Without the use of synthetic fertilizers, this is natural hydroponics at its best.

Left, Right and Below:
Aquilegia canadensis (wild columbine),  Ilex verticillata (American winterberry), and Sedum spathulifolium ('Cape Blanco' stonecrop).
This Sedum from Oregon is a favorite food for the pika (a small relation to the rabbit).  In the spring look for a bright yellow flower that stands out against the lichen.

Trying to duplicate Mother Nature’s efforts is no easy task.  In nature plants adapt and are conducive to the environment; they are naturally at home.

Installing a hydroponic living wall is relatively easy; the challenge is to meet all the needs of a plant pallet that is part of the man made ecosystem - totally unnatural and more times than not combining plants that are not of the same needs is the main reason for failures.

Hydroponic living walls are also much different than the traditional horizontal technology developed to grow food.  For starters, the living walls are vertical unlike food producing units that are horizontal, even if they are “stacked” as towers and allow the vegetation to climb vertical (Green Façade).

Before we talk about the DIY materials and “How To” part, let’s start with the types of hydroponic systems available.  There are active and passive hydroponic systems, easily remembered because “active” means with a mechanical pump (which is the common for hydroponic living walls).  In an active system, moving water is infused with chemical nutrients as it passes over the roots.  A passive system works without a pump and utilizes a wicking fabric or some type of inorganic media that that draws water to the roots.  The green wall systems I have had the opportunity to trial and work with have a combination of materials, everything from felt, to cleaning scrub pads (mineral wool), plastic, poly vinyl chloride (PVC) and coco husk, and they all rely on a mechanical means (active system).

I have not found one single combination of products and techniques that make hydroponic green walls a foolproof method.  Some are much more successful than others but not without attention to detail and intensive maintenance requirements.  In a natural occurring living wall the plants that are native to the surroundings are adapted to the conditions.  “Conditions” refer to elevation, lighting, nutrient availability and in nature only plants that are adapted to the present conditions will continue to thrive.  In the living wall the task of plant survival is put on the installer, system type and the expertise of the maintenance technician.  Just because you are a landscaper or interior plant company, don’t assume you’re going to be able to jump right in and master hydroponic living walls - there is a learning curve.

I do have relationships in the industry, some of them with national companies; they maintain both media /soil based walls and other hydroponic walls.  The maintenance on the hydroponic walls is a break-even scenario for them because of the higher than average maintenance needs.  The variables and conditions are ever changing and having the ability to meet the maintenance needs and upkeep is an education only experience can bring.

Here is that “fine line” between success and failure.  Many variables are under constant monitoring in order to be successful.  Hydroponic living walls are seldom 100% lush and thriving all the time because of the ever changing variables with very little room for error.  Even a slight change in temperature can disrupt the dynamics of the wall causing massive areas of die-off; we will talk more on monitoring the walls later.

Hydroponic Living Wall: Basics

Hydroponics require many variables to come together in sync in order to be successful.  My own reading suggests that experience and education are a must before diving into hydroponic growing.  For the most part, common landscapers and indoor plant companies are usually not at the level of expertise when they decide to either install or take on the maintenance of a hydroponic living wall.  Medias / root support structures, clean water, temperatures, pH levels, lighting, nutrient solutions, and oxygen exchange (oxygen to nutrient ratios), are part of the synchronization of successful hydroponic walls.

Hydroponic living walls start with some type of waterproofing to protect the structure behind the wall.  There are common water proofing membranes, peel and stick applications, PVC sheets or in some cases I have seen layers of felt stapled directly to a concrete wall.

Rooting Media

Felt fabrics, coco husk and porous sheets of scrub pads (mineral or rock wool) and porous foam are the most popular types of rooting media materials.  There are many varieties of applications for each of these products – again, I’m not partial to one particular material and I have seen various results with some better than others.

Left to Right: hydroponic capillary mat; felt fabric; capillary fabric with plastic lining and geo-textile backing (manufacturers unknown);

Deciding on what fabric or media to use can only come through experience.  Personally I have documented and found high amounts of root and crown rot in all the media types shown here.

Left: 3M Doodlebug close up, 56” wide, by 42 yards long @ $32 per yard; purchase information contact: Joe Koszarek, Beacon Lighthouse Inc.; Right: Nedlaw Hydroponic Living Wall constructed from two layers of similar 3M Doodlebug scrub pads in larger rolls prior to being cut.

Coco husk block inserted into a geo-textile bag by GSky.

Left: Polyester weave (manufacturer unknown); Right: open cell polymer foam blocks similar use by Eco-Walls; purchase information contact: Chi Meng 

Avoiding Root Rot & Other Potential Issues

According to Wikipedia, "In hydroponic systems inside greenhouses, where extensive monocultures of plants are maintained in plant nutrient solution (containing nitrogen, potassium, phosphate, and micronutrients) that is continuously recirculated to the crop, Pythium spp. cause extensive and devastating root rot and is often difficult to prevent or control."

Root rot can occur in hydroponic applications, if the water is not properly aerated.  The root rot affects entire operations within two to four days due to the inherent nature of hydroponic systems where roots are nakedly exposed to the water medium, in which the zoospores can move freely. (

Hydroponic living wall showing signs of both crown and root rot.

Symptoms include leaf drop, yellowing & discoloration.

It is typical that root rot is the result of an anaerobic environment.  (As we continue I will explain the importance of balancing nutrients and oxygen exchange.)

Root rot evident sandwiched between two layers of 3M Doodlebug.


Distinct onset of root rot, this particular plant will last another 24-72 hours.

Other factors include: unsterilized tools and equipment, unfiltered water, dead roots and leaves, other infected plant material.  As a former landscape contractor I know personally what it would take to sterilize my tools to work on such a wall - frankly, it may be too much trouble.

This is one of the reasons the cost of maintenance is high.  The preventative labor is equal to the actual labor pruning and replacing of plants.

Hydroponic Living Wall utilizing open cell foam showing plant loss due to crown and root rot.
Obvious signs of yellow and discolored leaves, leaf loss and plant deterioration.
This hydroponic living wall shows a variety of symptoms that include: Root rot, discoloration, crown rot and algae build up. If you look closely you will see some naturally formed lichen and the burnt tips of the leaves that may be caused by salt build up or over fertilizing.

Because of the constant presence of water, hydroponic living wall media can become a breeding ground for algae and gnats.  Keeping the plants healthy, vigorous and stress-free is the best "cure" against Pythium.  Pythium is almost impossible to 100% eradicate from an infected system; this involves starting completely over with new plants, containers, equipment, etc.

To remedy the wall you will have to disinfect the entire system.  Manual scrubbing and bleach might be necessary, adding tap water, and disinfecting the water with strong hydrogen peroxide (H2O2).  The solution will require 100ppm to kill pythium - however, this can also kill small plants.  Wait 24 hours for H2O2 to dissipate to a safe level; do not add more water to system!

Add only H2O2-treated water, add nutrients and beneficial enzymes.  The aerobic-loving enzymes will colonize the sterilized medium and system, hopefully displacing any of the anaerobic bacteria.  Starting with a clean system is the best prevention.

Below you can see leaf build up at the drain (right) and fallen leaves rotting on the left.  These dead leaves become food for the Pythium.  This is also true with algae.  Algae will eventually dry, die and become organic material, fueling Pythium fungus.  Once started it becomes a vicious cycle without sterilizing the entire wall.  There are chemical / biological preventatives; I would suggest going to talk with your local hydroponic store.

Left: Leaf build up; Right: Rotting leaves.

Once you decide on a rooting media, having clean water is not an option.  Some professional growers will use distilled water and this is much more expensive; however, hydroponics are very sensitive to salts, pH and changing variables including temperature.  The water is a vehicle that transports a nutrient solution to the top of the wall via a pumping system and allows it to saturate the rooting media via gravity from the top down while bathing the roots.

All plants need key macronutrients: Nitrogen, Phosphorus and Potassium lead the list of “must have” chemicals:

Nitrogen (N) —promotes vegetative growth
Phosphorus (P)—contributes to healthy roots and flower blooms
Potassium (K)—important to fight off disease and resistance to pests
Sulfur (S)—health and improved color of the leaves
Calcium (Ca)—promotes new root growth
Magnesium (Mg) chlorophyll—contains a Mg ion that improves food production

In commercial fertilizers the N, P & K are depicted by numbers in ratio to the weight of each one.  For example 10-10-10 is a balanced ratio of N, P & K.  In contrast, 25-5-5 will provide a quick rapid greening of the visual leafy portion of the plant with only 1/5th the P & K.  Boron (B), copper (Cu), cobalt (Co), iron (Fe) manganese (Mn), molybdenum (Mo), and zinc (Zn) are micronutrients responsible for a myriad of tasks including: cell wall development, nitrogen and sugar metabolism, protein synthesis and water loss just to name a few.

Vegetation acquires these micronutrients directly from natural growing media; commercial producers of fertilizer do not include them for typical landscape and crop applications, but because the hydroponic technologies for living walls do not include a growing media that can hold nutrients, the nutrient solution MUST include these essential micronutrients.

This is where inexperience becomes costly.  If you are not trained nor have experience with vegetation for hydroponic living walls, the risk may outweigh the glory.  This is not a project you want to experiment with a client.  You risk reputation and serious monetary loss simply through maintenance and plant replacement.  I mentioned earlier we work with a very experienced indoor plant company who is happy to break even on the maintenance of the hydroponic living walls they maintain.  They keep the wall as part of the overall maintenance account for the building.  There are many over the counter pre mixed nutrient solutions available; contact your local hydroponic supplier for more details.

(For an interesting debate on Organic vs. Hydroponic Growing, visit Jungle Walls by Peter Kastan.)

Once you add plants, the variables will continue to grow from here, no pun of course.  You have to find a balance between nutrient solutions, pH levels, temperatures, lighting, and dissolved oxygen.  All of these variables must be in alignment for a hydroponic living wall to work.


pH is a scale from 1 to 14 that measures acid-to-alkaline balance:  1 being the most acidic, 7 is neutral and 14 is most alkaline.  Every full point change in pH represents a 10-time increase or decrease in acidity or alkalinity.  For example, soil or water with a pH of 5 is 10 times more acidic than water or soil with a pH of 6.  Water with a pH of 5 is 100 times more acidic than water with a pH of 7.  With a 10-fold difference between each point on the scale, accurate measurement and control is essential to a strong, healthy garden.

Most plants grow best with a pH between 6.5 - 7.  Within this range, plants will absorb and process available nutrients most efficiently.  If the pH is too low (acidic), salts bind nutrients chemically, and the roots are unable to absorb them and the plants won’t feed.  On the flip side, an alkaline soil with a high pH causes nutrients to become unavailable.  Toxic salt build up that limits water intake by roots also becomes a problem; get to know your water.

Hydroponic solutions perform best in a pH range a little lower than for soil.  The ideal pH range for hydroponics is from 5.8 - 6.8, slightly acidic.  A bi weekly test should be part of the maintenance process; adding products to pH up (potassium hydroxide and potassium carbonate) and pH down (Phosphoric acid) add cost to maintain the hydroponic living walls.

Water Temperatures

The amount of dissolved oxygen in a nutrient solution depends on the water temperature.  Cold water can 'hold' more dissolved oxygen.  A fully aerated solution at 20°C/68°F is 9 - 10ppm; at 30°C/86°F it's 7ppm.  According to Dr. Lynette Morgan, Director of Research at SUNTEC International Hydroponic Consultants based in Manawatu, New Zealand, root oxygen requirements double for each 10°C rise in root system temperature (max 30°C/86°F).

The dilemma for the maintenance technician is that with a 10°C rise in temperature, root system oxygen requirements will double, while the oxygen carrying capacity of the solution will drop by over 25%!  The nutrient dissolved oxygen is unable to supply the roots’ oxygen demands, leading to prolonged oxygen starvation.  Oxygen starvation will result in slow growth, mineral deficiencies and root die-back.  Oxygen starvation will stress the plant, leading to an eventual attack by opportunistic pathogens, such as ever-present pythium aka root rot.  What Dr. Morgan is describing is the anaerobic environment that is the naturally occurring environment of hydroponic systems.

DIY Equipment & Set Up

For the most part the equipment needs are pretty simple.  Assuming we are talking specifically about hydroponic green walls – I’m not going to talk about ebb and flow nor aeroponics - specifically we are utilizing a top feed configuration; water solution is pumped up and allowed to drip through the media back to a reservoir.  Pending the size of your wall, freestanding or wall mounted, you need a reservoir, pump, inorganic media (what will physically hold the plants), test kits and sterile tools.

For a reservoir the basic of plastic containers will work fine depending on the size of your wall. Some more advanced applications also contribute to the cosmetics of the system; stainless steel and decorative pools are not uncommon but because of the sensitivity of the solution, the exposed reservoir is subject to becoming a catch all for garbage or debris immediately altering the dynamics of the pH.

As a word of caution, take careful consideration of your reservoir as it is the life line to the success of the wall.  For larger walls and walls exposed to evaporation, a fill float can be retro fitted to the reservoir.  The color of your reservoir will also play a part in the water temperatures.  As we discussed earlier, higher water temps result in less oxygen!

There are also a variety of pumps available; my experience as a pond builder would lead me to the magnetic drive types that seem to last more over continuous use.  When choosing a pump the key is to understand how much water you need to pump at what rate and the height you have to pump it.  The key here is what we call the “Head Height” or maximum height the pump can push water.  Head is measured in length and the pump capability of flow vs. height.

For example, the height from the top of the reservoir to the top of the wall is 10 feet.  Searching the internet we find literally thousands of options.  A statistical rule is to double the psi (pound per square inch) to determine the head in which the pump will pump zero gph (gallons per hour).

Table 1.

Table 1 shows the actual “Head Height” taking into account the reservoir is not part of the calculation.  When configuring the actual pressure needed to reach the maximum height, the equal distribution of water going through the pump through the supply tube while it is in the water is equal to the water weight outside the tube until it exits the reservoir when gravity and the actual weight of the water in the tube come into play.

Table 2.

Table 2 is a common and easy means in which you can determine what the minimal needs would be to reach the height needed to irrigate your wall.

The life line of the system can be viewed as if it were a human.  The pump is the heart, the tubes are veins and arteries, and the solution is the blood carrying nutrients to the remainder of the body - all must be in working order.
Constructing Your Hydroponic Living Wall

For the most part the steps are simple.  Start with deciding on an area with good light and recirculation air flow.  I have seen various types of armatures that are  tapered from the top of the wall down to the bottom so we end up with about six inches from the bottom of the wall.

Figure 1.  In most cases the walls are flat at a true 90 degrees.  This tapered angle, however, will prevent the irrigation water from dripping off the leaves allowing it to follow the angle of the rooting media.

Figure 1:
Vegetation angle

The following sequences of pictures are from Peter Kastan and provide a real hydroponic wall installation: 

Step 1: Armature and Mounting Framework

Source: Peter Kastan

Step 2: Mounting the PVC Sheets
(Purchase at Home Depot or similar store) 15 – 3 f2 sections @ $39.96.

Source: Peter Kastan

Step 3: Mounting the Rooting Media
(Geo – textile, open cell foam, coco husk, Doodlebug Rolls, etc.)

Source: Peter Kastan

Rooting Media Complete, with Partial Plant Installation:

Source: Peter Kastan

You can visit Peter at

Going the Single Source Manufacturer Route

It may seem I'm pointing out a lot that go wrong with a hydroponic living wall system, but that is the point when dealing with a DIY project in particular.  Of course, you have the option of choosing a patented hydroponic living wall system if you don't choose the DIY route.  The greatest issue to consider here is scale and cost - of the system itself, installation, and maintenance plan.

While most of us probably can't afford Patrick Blanc and his Le Mur Végétal (Vertical Garden) living wall system, there are other proprietary hydroponic systems to consider - here a few:

Patrick Blanc and Le Mur Végétal at Capital Land in Singapore.

Nedlaw Living Wall at TRCA in Toronto.

The EcoWall™ at a private residence in Philadelphia.

There is a lot more to hydroponics than a simple pump and solution to feed the plants.  And, living walls are not for the faint of heart when it comes to experimenting with someone else’s investment.  When going DIY, my advice is to try various materials that are locally available, get advice from your local hydroponic supplier and set up your own trials and research.

I have pointed out some of the variables that will determine your project a success or a maintenance catastrophe.  There is much more to the hydroponic living walls, including the highly variable topic of plant material – both inside and out – and I have only scratched the surface of the many highly advanced systems and applications.

George Irwin, The Green Wall Editor

Green Wall Deception, Death of a Green Wall…

By George Irwin, The Green Wall Editor
September 2, 2011

Let me premise this post as a reality check for living walls.  No pictures, no examples, just my opinion.  Over the years of my experiences of trials, I’m seeing living wall failures masked with pictures and unreal expectations.  Like the stock market, it is time for an adjustment to bring this industry back to a beneficial level of reality.

It has been over three years since my first post about Green Walls (March 2008).  Since then we have seen a rise in popularity for green walls being used in advertising, cosmetics, and urban agriculture, with claims for green walls acting as additional insulation, adding 30 points to LEED credits, and even cutting electricity by 20%.  In short, some of the pictures and the statements advertised are bordering on blatant fabrication.

In the 1990’s and 2000's it was Patrick Blanc's innovative hydroponic system leading the way and hoarding the attention for his lush, bountiful displays.  Through his example, many, including myself, saw the potential of this industry.  Today there are more than enough newcomers, some blatantly knocking off patented technologies; I can’t keep up with the system designs and claims.  Plastic boxes with bags, wire mesh with jute fabric, racks that hold potted plants, Do It Yourself felt fabrics, most of these are deemed “One Time Use” with the development of such products destined to becoming a novelty with no proven longevity or use beyond a single outdoor growing season, not to mention becoming a potential safety hazard if hanging more than six feet off the ground.

Personally, I have read recent blogs and articles painting living walls in a negative light questioning the viability and longevity of green walls.  Fair enough, you don’t see websites that highlight the failures.  To my own testament, I, too, have had a wall removed because of the lack of experience from a maintenance perspective.

Since 2007 I can attest to my own development and data collection that has lead to our improved maintenance techniques, dramatically improving survivability.  However, I have never seen a reduction of electricity by 20%, and a recent article explains how some systems actually cause a greater carbon footprint than they purport to reduce.  Is it green wall deception?

There are many products available to the consumer, contractors, and various installers yet, in my opinion, a large majority of  these lack the training and education to maintain the green walls after the installation.  Let’s face it - the ability to use a level, cordless drill and a little physical exertion doesn’t make you a green wall expert.  It is not only the system's design that's important, but the long term science and know-how that provides success: it’s the service after the sale.

And the greatest learning experience is a failure.  Failure has been, frankly, my own motivation for improvement.  The issue in the industry, and specifically with a few of the systems, is the fact they do the same thing, time and time again expecting different results.

I have seen everything from green roof media to top soil being used as a growing medium for living walls.  Some now use a coir husk that simply acts as a holding mechanism for a root structure, while the chemical bath keeps the plants alive, or at least that is the way it’s supposed to work.  The structural advances of living walls are far and few.  As mentioned earlier, racks to hold potted plants, boxes with bags and felt pockets are nothing but a means to hold plant material.

The real advances are now in the growing medium and improving holding structures that promote healthy plants.  The science behind the system is what will prove viable, long term success.  Getting back to my earlier point, just because you can use a level and cordless drill does not make you a green wall expert.  The true success is being able to sustain the walls in a manner that will prevent plant replacement year after year, or in some cases on a weekly basis.

The amount of knowledge needed for success in this arena is overwhelming.  You have to be an expert in design, irrigation, indoor and outdoor plants, growth media, lighting, pest and disease management and fertilizers; this doesn’t sound like your average contractor.  To compile the problem, there are more than enough bloggers, architects, designers and members of the industry who seem to have all the answers.  There is more than enough information, some good and some not so good, in cyberspace to confuse anyone, if not everyone.

I believe living wall success will rely on the combination of skills from an individual or company that offers services from concept, installation and maintenance to long term warranties.  Recently I heard of a wall being installed at a high profile college outside of Philadelphia where the owner was told, and accepted the fact that, “All the plants are going to die and will have to be replaced after the first year anyway.”  This was astounding to me that such an assumption was even remotely acceptable.

The reality of living walls is the long term education and training that is associated with the ability to apply multiple disciplines.  I’m going to quote myself, “If you have a potted plant and you place it in the dark closet, you don’t water or feed it and the plant dies, do you blame the pot?”

The same is true with living walls, you have to accept and understand that living walls require an extended know-how that cannot be provided by every landscaper, contractor and architect.  The most frustrating situations for me have included the project owners who insist they can maintain the walls.  This does nothing to help solve the failure rate and it puts living walls in a bad light when one does fail.  These systems are not maintenance free.  Providing a plant the needs to survive on a wall, at times over 10 stories high, is not a feat for the inexperienced, yet some consumers are fixated with the allure of living walls with little to no understanding for long term maintenance and survivability - and for that fact neither do some of the existing manufacturers.  Designing and creating a holding structure is a far cry from being able to sustain the long term health of a living wall.

The other complicating issue involves the hype of the real benefits of living walls.  Fact is I have personally yet to see any long term data that can prove anything concrete other than aesthetic improvements.  I have posted our own data about the findings of our field studies, however, I have yet to see any formal long term data on energy savings.

One website claims that the living wall will protect the façade.  Here is one piece of reality: rhetorically speaking, can I justify a living wall at the cost compared to the exterior façade replacement?  Green walls will protect the façade, however, the façade is designed for the exterior use anyway, so by protecting it where is the real return on the investment?  Where is the payback?

Preparing the façade and façade penetrations don’t protect a whole lot of anything, in fact you have now damaged the façade via the penetrations.  Also, if the manufacturing system representative you chose is not knowledgeable about plant material, did you account for the potential plant replacement?  And show me a living wall that can provide 20% savings on electricity, I would love to see it.

But not all is negative!  I do agree the walls provide a wow factor and benefit employee production, improved air quality, improved acoustics and can be a viable use for urban agriculture, but that’s only if they don’t fail, require high numbers of plant replacements, or just outright become a burden.

Are all green walls to be classified as sustainable?  No way, not in my book.  For one, some of the materials used to manufacture the units are in question.  For example, one common material is plastic which in itself is not a sustainable material.  In fact, LEED prefers the use of metal over plastic, making the LEED points applied to plastic systems contradictory.

Never thought I would be the one to write such a post but I’m a realist.  The point of this post is not to give living walls a bad rap; in fact, the intention is to bring to light the reality of what can go wrong and how little the industry and many installers truly know.

My responsibility as an educator and an authority on these technologies is to protect and inform.  The best use of failure is to learn from it and not repeat our mistakes.  I'm sure others are not selling walls hoping they fail, but many people forgo needed changes just for the sake of another sale.

Although others are planned, currently there are only a few university green wall system and benefits testing going on in North America - BCIT and Maryland - and these studies will eventually help the industry and hopefully prevent dreaded deaths of green walls.  Yet for now, consumers beware.

Designers, architects and consumers, my advice is to move forward with living walls under the pretense that not all are created equal and each system has its own application.  Hydroponic vs. media-based are only two technologies.  Educate yourself and gain an understanding of the science behind each system.  Know you must be invested in your purchase in order to increase the likelihood of survival. 

I have seen some beautiful successful walls, both interior and exterior.  The success of such walls are the result of a well rounded research, design, training, installation, and maintenance program.  Utilizing the right plants in the right setting for the right system as well as understanding the science behind the technology are key to your green wall's longevity.

George Irwin, The Green Wall Editor

George Irwin is the President and CEO of Green Living™ Technologies, LLC (GLT) based in NY.  Green Living™ Technologies is the only U.S. manufacturer of growing media based green wall and three types of green roof systems.  Mr. Irwin is a former trainer for Green Roofs for Healthy Cities Green Walls 101.

Contact George Irwin at:,,, or 1.800.631.8001.

The Next Add-On Service for Green Roofs and Green Walls

By George Irwin, The Green Wall Editor
May 24, 2011
Photos Courtesy of George Irwin, unless otherwise noted.

Last time I told you how I was long overdue for a new column post but was torn between two topics of interest, remember?  Well, after Green Walls and Winter Interest, here's the second one - my take on the latest profitable service for landscape contractors, roof garden and green wall professionals and garden lovers alike.

The agriculture industry has evolved to create one of the most diverse and competitive industries for contractors, architects, landscape architects and designers. The economic downward spiral over the years has placed more pressure on companies to sharpen budgets and to offer additional diverse, one of a kind type products and services.  As a business, you have to truly think about the services you offer that will make you stand out, focus on the ones that are profitable, create acceptable profit margins, and attract clients that warrant a professional.

If you recall the boom in pond installations starting in the 90's, everyone wanted this exclusive water feature and, of course, at one time only a handful of companies offered such a “specialty” service.  Yet eventually, after someone does something so successful and spectacular it tends to evolve into something more mainstream.  These specialty services are also often new to a company, and success rates, knowhow, and the unknown can be initial hurdles.

Tomato & basil on an A-frame.

After some needed training and experience, we know the modern development of green roofs and vertical walls provided add-on opportunities for landscape/construction, design/build, design, product manufacturing, nursery growers, irrigation and long term residual maintenance professionals.

So what is the next great service, you ask?

Small scale backyard farms of edible landscapes are the new “pond building” boom, and edible walls and roofs are the new landscape.

Although we are not seeing the green roof residential market competing with the commercial, education or government sector in terms of economic scale, there is a continuous growing trend towards residential and small commercial scale urban farms.

Currently, there are a handful of companies in the U.S. who have added edible landscapes as part of the service package they provide.  On a larger scale, commercial urban farms are far and few but gaining popularity.  And these urban farms can include everything from design services, installation, and maintenance to harvesting.

Urban farms are an amazing add-on feature for the green roof and wall market with great potential, and now commercially available vertical agriculture beyond conceptual stages are taking the industry to higher than average profits, showing a return on the investment of around one to two years.

Dragonfly, a stunning conceptual" Metabolic Farm for Urban Agriculture" for NYC  by
Vincent Callebaut Architectures.

Peppers & greens together in a green wall.

Each year after operating expenses, returns on the initial capital investment can be 50% - 75% of the initial investment.  Unlike ponds or water gardens, food is not an option and the public awareness and desire to have high quality, fresh produce close to home is a market virtually untapped with an unprecedented promise of success. 

Opportunities now exist for the new corner store to become the state-of-the-art vertical farm backed by organic and food safety certifications that can grow everything from tomatoes, greens and specialty crops year round, indoors, in almost any building.

From small scale residential raised beds to simple but sophisticated larger vertical farms, fresh produce has evolved as the next service for the landscape industry.  And, the burgeoning trend in rooftop agriculture is providing an as yet untapped boom for the green roof industry.

Rooftop farms are beginning to bring some fame, and if not yet fortune, certainly lots of media attention due to the newness factor.

See the not-so-small 40,000 sf Eagle Street Rooftop Farm below:

Eagle Street Rooftop Farm, Brooklyn, NY
by Annie Novak, Ben Flanner, and Goode Green.

In recent years there has been a clear increase of public awareness and educational programs around urban farming and produce, from professional organizations like Green Roofs for Healthy Cities to non-profit organizations such as Urban Farming to private companies like many of our own collaborations here at Green Living Technologies.  The consumer market is reaching out and craving for these products - restaurants, school lunch programs, classroom education, etc., and I believe the public “urban-you pick-it” is the next franchise model.

Different kinds of lettuce in one green wall module.

Recently, I had the chance to host a training at one of the largest hydroponic tomato growers in the U.S. northeast at an incredible 12-acre facility heated with methane gas costing very little to heat after the initial investment.  The potential for large scale food production is great, yet we recognize the need to diversify hydroponic technologies to include new and improved techniques.  By advancing this successful model with incorporating additional vertical technologies, we’ll have the capability to produce crops beyond just tomatoes. 

Rows and rows of hydroponically grown tomatoes.

Although this large scale commercial facility services large clients such as grocery stores, it is the smaller, more personal one-on-one customer relationships that will provide the greatest potential for truly local produce, plus possibly provide the highest margins for the edible landscape. Of course, both the large and small scale urban ag growing facilities have their place in the market for food production, but the point is we need to diversify our crops to reap the greatest rewards.

For hundreds and thousands of years, people, communities, and cultures have always come together over food and a meal.  Not only would these future urban ag centers provide healthy local food but they could also be the catalyst for bringing communities back together, wouldn't you agree?


George Irwin, The Green Wall Editor

Green Walls and Winter Interest

By George Irwin, The Green Wall Editor
Photos Courtesy of G-Space Design, Project Manager and Certified Product Installer
March 18, 2011

Green Walls can’t survive in the cold; they don’t look good in the winter; they are only viable in the south or indoors…..Think again!  There is more science behind a green wall than you may think.

I am long overdue for an updated article but was torn between two topics of interest.  I was set on talking about the latest profitable service for landscape contractors and garden lovers alike when the timing couldn’t be better talk about these green wall images I recently saw in a newsletter.  The winter interest is just as dynamic and provides incredible pallets of delightful colors.

What happens in the winter?  Read on my friends and lovers of vertical bliss.  It’s time to put an end to the banter about green walls and winter.  Not only can they survive, they can be gorgeous!  I was reading the newsletter from Michael and Angela Bucci, owners of Philadelphia based G-Space Design and Philly Green Wall & Roof where they featured multiple walls that display just as much interest in the winter as they did in the spring and summer.

The wall below is one of many at this particular location in the Philadelphia area.  I enjoyed this wall the best, with the enhanced purple and red ground cover providing an accent to the blue in the wall.  The transitioning from late fall to winter is undeniably just as interesting as the blue becomes brighter and the purple gets more intense, all while retaining a green surround.

Photos Courtesy of G-Space Design

Philadelphia, PA Green Wall
Left, October 3, 2010; Right: January 6, 2011.

The success of the wall is all about knowing how the plants react in their geographic region and elevation.  Specifically, the Mondo Grass keeps a green color, tips have browned; Hosta Francine is completely dormant, all leaves have browned; Blue Star Juniper turns a bright slate blue color; Lysimachia aurea has some brown and drooping leaves; Huechera Purple Palace displays bright purple, Purple Phlox has some green retained and the Sedum ternatum shows bright green color all winter.

Without disclosing all the science behind the success, I will tell you that much of what we see here is due to preventative maintenance.  This is not to say there have not been extensive trials and, in fact, mistakes.  Some plants simply don’t provide winter interest, like the hosta or other perennials.

Below is the noted PNC Bank, still the largest exterior wall in North America and by far one of the showiest as the color variations provide both texture and contrasting variations as the seasons change.

Photos Courtesy of G-Space Design Photos Courtesy of G-Space Design Photos Courtesy of G-Space Design

PNC Bank, Pittsburgh, PA
Left: September 16, 2009; Middle & Left: 1st winter 2010.


Photos Courtesy of G-Space Design Photos Courtesy of G-Space DesignAjuga 'Black Scallop'
Carex 'Evergold'
Huechera 'Purple Palace'
Lysimachia aurea
Sedum ternatum

PNC Bank
Left: September 2010; Right: 2nd winter February 23, 2011.

When we teach maintenance, it’s not so much the amount of pruning and time on a lift or ladder (I wrote about maintenance in October of 2008).  Besides having access to the wall, following a standard irrigation checklist and keeping the catch basin clean, the preparation for the winter is one of the most important maintenance visits throughout the year.

Unlike plants in the ground which are protected by snow, mulch, and other wind deterrents, green walls are subject to harsh conditions yet the plants are unlike traditional sedum for green roofs and are susceptible to the enhanced and harsh conditions of winter.  Much of the decorative walls are not sedums and can be very delicate, making them susceptible to the harsh winds.  Wind tears at leaves and removes moisture from both the plant and the growing media.  The key is to prevent the plant from losing moisture during the winter months.

We protect the green wall from moisture loss two ways.  The first is a trade secret, but the second I’ll gladly disclose and say that periods of warming provides an ideal time to irrigate the walls in the winter.

YES….the irrigation should be turned on when there are breaks of warming from 35 degrees or higher.  Microscopically, the roots are seeking water during these times and without it the plant will die.

Photos Courtesy of G-Space Design Photos Courtesy of G-Space Design

Philadelphia Gateway Project: Summer of 2010

Dwarf Mondo Grass - mostly brown, some green at base of leaves
Sedum rupestre 'Angelina' - reddish orange color
Sedum 'Blue Spruce'
Sedum album 'Red Ice' - reddish color

Photos Courtesy of G-Space Design

Philadelphia Gateway Project: February 8, 2011

It has been a thrill to be part of an industry where there is a handful of successful science based green projects.  On the other side, it is the new opportunities to create jobs and provide the next new paradigm shift in technology that is exciting.

Planting a wall and hanging it are only the beginning.  There is science behind success.  The failures could be linked to many variables including product, growing medias, plant choices, irrigation and much more.

I feel there needed to be some clarity on the subject that not all green walls - and the experience behind them - are linked to the industry as a whole.  Not all green walls can survive the winter, however, many can while providing much needed winter interest from the living, breathing, plants.

George Irwin, The Green Wall Editor

The Original Green Living Wall:
Basis for Great Design

By George Irwin, The Green Wall Editor
Photos Courtesy George Irwin Unless Otherwise Noted
September 26, 2010

Mother Nature: A great designer!

When something is successful it’s only natural to emulate that same success.  Green wall technologies are no different.  As the owner of three patents, I find myself grinning in disbelief that someone would think so highly of what I have invented to copy it as their own.

Laws today prevent intellectual property from being duplicated, however, Mother Nature cannot be patented.  No one company or person has claim to inventing the Living Wall except for hers truly, Mother Nature.  Since the days of time, plants have been growing vertically!  I want to take a step back and look at the science and beauty of natural green walls and how the principles are applied to some of the technologies available today.

The vitality and survival skills of plants are remarkable, provided an opportunity they can adapt to the climate and location.  Through the process of phototropism, growing to the light source, plants increase vitality and survival rates.  Below are clear pictures of celery and broccoli growing out from an edible wall to the light source literally growing out of the wall and turning up at a 90 degree angle. This has been true with other vegetables and green wall plants. (For sake of argument we are specifically talking about “Living Walls” only.)  Even when bearing heavy fruit, the stems of the plant reach for the light.

Celery & Broccoli – Reaching for the light from an edible wall.

During my lectures, I refer to living walls as a pot that can be elevated to hang on walls (or freestanding) - it’s not that simple but my point is, if you have a potted plant and you put it in the closet and it dies do you blame the pot?  Of course not, plants like people, have needs.  For the sake of this article, I am not going to address the obvious elevation and lighting needs.  Not all plants (or living walls) are created equal; the amount of sun and elevation requirements are unique to each plant variety.

Ferns, mosses and more creating a natural
interwoven vertical tapestry of plants.

The key features behind successful living walls are those duplicated by nature.  The definition of Living Wall includes a root system throughout the entire structure, either with or without growing media.  There are a variety of individual plants throughout a wall, depending on the geographic region, each with its own root system.
In my opinion, in order to create a successful wall, plants need a structure or mechanical method to anchor and areas for the roots to expand and “Grab.”  In the natural living wall, this can be seen as plant roots traverse through cracks and crevices (above).

Figure 1 below shows the extensive root system that stabilizes the growing media and locks the plant into the system.  Even mosses microscopically grab the rough surfaces of the rock face.

Figure 1: Cutout of the developing root system.

There are more successes with commercial living wall systems that allow for the “Grabbing” action of the roots.  Larger pockets or bagged areas won’t allow for the roots to grab, but instead literally hang in a fabric mass of contained roots and growing media.  That’s not to say all the living wall systems with structured cells are complete.  In some cell technology systems, the configurations do not allow for the roots to migrate or at least enough to accommodate the fullest needs of the plant.  This incomplete configuration does not provide areas for the roots to expand, and eventually creates a series of root bound plants, something to consider when choosing a system.

Figure 1 shows the natural development into the pockets between the rock face and grabbing power as the crevices act as areas for the roots to anchor.  These crevices could represent the cell structure of an artificial living wall system.

Left: Bagged type Living Wall showing signs of pressure pushing the front wall forward.
(Red line shows the bend.)
Right: Close-up of the bag protruding through the framework.

Stabilizing the plant is only one element to successful man made walls.  Duplicating irrigation and nutrition can be tricky since stormwater is the source for natural green walls.  Because they are vertical, it is easy to see that water runs off from the ground above and down along the walls bathing the plant and roots.  This water will contain the natural nitrogen (N), phosphorous (P) and potassium (K) for each region, in addition to the trace minerals that will naturally feed the plants - does this sound familiar?

One designed form of growing plants is the technique of "aeroponics," the process of growing plants in an air or mist environment without the use of soil or an aggregate medium, bathing the entire plant while providing small and short does of synthetic fertilizer.  This method of growing was originally developed by NASA to grow produce in space when the astronauts were orbiting for extended missions.

Similar to aeroponics, the second technique of growing without a form of media is hydroponics.  According to Wikipedia, plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, or coconut husk.  The techniques are both reliant upon a chemical solution to provide plant growth.

Figure 2. Left: Aeroponic growing (; Right: NASA plant physiologist Ray Wheeler checks onions being grown using hydroponic techniques (

Famed French botanist Patrick Blanc created his hydroponic Mur Végétal (Vertical Garden) living wall system attempting to copy what Mother Nature has accomplished, at least in the irrigation methods, with waterfalls as an inspiration for his soil-less walls.

Blanc's methodology was born from his time spent in tropical forests; his design is simple in theory, duplicating the natural plant baths of nutrient rich rain water.  However, I believe the ecological factor of some of the materials are in question, specifically the waterproof sheathing, made of polyvinyl chloride (PVC).

There is a wicking felt layer with pockets to hold plants; water is recycled with a nutrient bath of synthetic fertilizers.  The design, not difficult to duplicate, is visually effective and many times stunning, however highly mechanical.  In fact, if there were a mechanical failure or loss of power for extended periods of time, it is likely the plants would dry out and the wall would suffer a higher than normal plant replacement.

Figure 3: Close-up of the layers of Patrick Blanc's hydroponic green wall: steel frame, PVC, felt, plants.

This means of hydroponic design was conceived to duplicate the tropics, and in some climates the excessive water is open to a myriad of complications.  For example, hydroponic systems should be highly aerated to provide oxygen at the root level; the lack of oxygen and warm root temperatures are the leading cause of plant loss.  Also, non sterile reservoirs are breeding grounds for water borne pathogens, such as "root rot," a generic name for Pythium, Verticillium, Phytophthora, and Fusarium, opportunistic waterborne diseases that can seriously affect indoor and outdoor plants.

There is another technique that combines bags, cells, and hydroponic growing.  The system contains bagged coco husk allowing for the roots to grab into the media as the bath of nutrients provides the life sustaining nutrition.  The benefit to such a system, if hydroponics is in fact the system you choose, is that unlike other hydroponic growing, the coco husk will provide a root area to grab onto and lock the plant in place.  The resource in question will always be the use of water and synthetic chemicals.

Hydroponic vs. Media Based Living Walls?

From my perspective, the advantage of a media based living wall lies in the fact that the media can support beneficial bacteria, micro-organisms, and provide a matter to hold water.  Some of these types of walls can go a week with no irrigation, and some indoor walls can go two weeks.  These micro-organisms need food to ensure they will grow and multiply, however, any harmful organisms will also feed and grow.  This is why it is important for free drainage and the ability for oxygenation. Harmful pathogens tend to thrive in anaerobic conditions, whereas beneficial organisms thrive in aerobic conditions.

Here is one of my secrets: Mycorrhizae.  Mycorrhiza is specialized fungi that colonize plant roots and extend far into the soil, and is a beneficial fungus that prevents pathogenic fungi from growing on the roots.  If you are growing in soil, in our case the GLT bioSoil designed specifically for our living wall media, including mycorrhizae is ideal - especially if you are feeding the plants an organic food.  In our case, we use a 10% blend of our bioSoil with mycorrhizae along with other matter that is proprietary. Mycorrhizae thrives with an organic food source.  Synthetic fertilizers destroy the mycorrhizae which is why they cannot be included as part of the hydroponic system, leaving the technology open to common root rot.

Vertical wall technology is pretty simple.  You have to provide a means for the roots to grab and lock themselves in, free drainage to prevent sitting water, proper means for root development, and choose the correct plant for the geographic region and elevation.

Nature's original green wall prototype with water running off the wall into a stream below.

Duplicating Mother Nature is no easy task - duplication and success are feats only few green wall companies can stake claim, and some better than others.  As a consumer, choose wisely beyond just a product price point.  The actual product - its function of replicating nature and its longevity, should be the basis of your search.  Green wall knowledge and plant science, service, reputation, and obtaining references are the best ways to determine what systems are right for you.

In short, find the longest lasting product from a manufacturer you can trust to weather the elements and a source who can provide the science and service to back up Mother Nature's original design.

George Irwin, The Green Wall Editor

Technology, Liabilities, and Growing Media:
Change is Good

By George Irwin, The Green Wall Editor
Photos Courtesy George Irwin Unless Otherwise Noted
April 21, 2010

Unlike the usual spring article when I'm usually complaining about being busy with tradeshows and with preparation for projects or travel, here it is April and I did not get my first article ready by February as anticipated. I’m much disciplined when it comes to getting things done on time, so I'll blame it on others around me for being so busy.

Our colleagues and clients are just as busy. Why is everyone so busy? I’m blaming technology. Before computers, PDA’s, cell phones, mobile Web and laptops, it actually took days to send a letter - now a million letters can
be sent in a single click, and the need for instant gratification sometimes supersedes quality.

The rise in technology has brought about change and, in most cases, change is good.  Products become better suited and applied, projects become bigger and more intricate.  The same is true for green walls.

In January I had a chance to be a guest speaker at the Tropical Plant Industry Exhibition (TPIE) in Fort Lauderdale, Florida.  One of the great things about being a speaker is you have an opportunity to walk the tradeshow floor, meet others who are doing research, propagate new ideas, form new relationships, and see new developing products.

Growin' Bag; Source.

2010 seems to be shaping up as what I see as the “Minimal Use Vertical Wall” with a handful of new green wall companies. Nothing bad about having a new company, we all started somewhere, however, not all green walls are created equal.  In fact, I have always talked about the advantages of products developed for long term use.  Let's face it, there are some materials we don't want, or trust, hanging on walls four stories high, but if you want to dress up your back yard fence with a lightweight option (re-planting them year after year), these minimal use green walls may be your answer. For example, there are plastic bags and canvas pockets that hang from a wall, another one that looks like a baby diaper pinned together, and the ubiquitous upside down tomato growing sock.

Yet as green walls become more popular, the projects become more intense, the spectacles become more dramatic - and so can the liabilities.  As an industry spokesperson and a frequent visitor to industry shows and events, two of many key questions I always seem to get asked include the liability of installing green walls, and type of growing media for green walls.

Notice that broken plastic is securing the product to the bracket.

First let’s talk about liability; here is where we may run into problems with new, unproven companies entering the green wall market.  Some of the products offered are for all intents and purposes, bordering on novelty or single season use (use it for one summer and throw it away).  For example, some of the products I have recently seen or experimented with are advertising and displaying higher mounting elevations than I would feel comfortable with installing.

There are very few commercial grade green wall products with a proven track record that are made to last indefinitely, constructed from materials to meet wind and weight loads, accommodate extreme variances in temperature and to withstand other regional abnormalities (e.g. salt tolerance around coastal regions).  Some of these new green wall products, specifically some of the living walls, have no track record at all.

Recently I encountered a press release from a “New & Exciting” company introducing green walls.  After some in depth investigating and direct knowledge, the company had no track record of manufacturing, installation, training, certification, or a portfolio behind them.

Who is qualified to install green walls?  According to the Chicago Tribune article "Turf wars, Chicago-style: Roofers vs. green-roof landscapers" of October 2009, the National Labor Relations Board (NLRB) favored the landscapers over the roofers to be capable of installing green roofs at a lower cost, and referring to roofers they pointed out that "they are no less experienced but are more efficient at installing green roofs.”

Green roofs, fine, there is more than enough training opportunities to learn about green roof installations; some companies provide a professional certification course that credits them to be "Certified Professional Installers" for that company's products, and other opportunities are more generalized such as the Green Roof Professional (GRP) accreditation offered by Green Roofs for Healthy Cities.

Understandable, and I accept the verdict by the NLRB hands down.  I do, however, have to speak openly about landscapers installing green walls.  Some of these projects, not all, involve a level of construction not normally associated with traditional ground elevation landscape work.  I can freely comment because I was a landscape contractor for 23 years before I, too, entered the green roof and wall arena in 1999.

In comparison to traditional built in place green roofs, for the most part a green roof tray system is relatively simple to install - once on the roof it’s a simple matter of safely getting the trays in position, and adding irrigation - which should be part of the landscapers' knowhow.  Overall, most roofers do not have the background or knowledge set to diagnose and treat problems relating to plant health, whereas the landscape contractor is ideal to be the stand alone green roof installer and maintain the vegetation.

Fig 1.  Proper scaffolding is a serious job.

Not to say all green roofs are that simple, but for this purpose it’s just not the same as green walls. There are no standards for green wall technology, with multiple systems to choose from including green façades and living walls (both growing media based and hydroponic).  Each system is different and each manufacturer should provide some type of formal, recognized training for a safe installation and the long term safety of an often large product hanging from a wall.

Some construction skills associated with the assembly of such systems require extreme measures necessitating specific training; it’s not about simply screwing brackets to a wall.  For example, one of my company's projects, the PNC Bank project in Pittsburgh, PA, left and below (Figures 1 and 2), was prepared by G-Space/ Philly Green Wall and Roof, a skilled, state licensed design/build firm certified under our product's brand, and not installed by landscapers.  The vegetation was already mature and grown into the system by a horticulturist and/or a growing facility, and thus did not need the additional plant expertise of an experienced landscape contractor.  In this case it wasn't about the welfare of the plants, but the physical installation including engineering, crane operations, calculations, mounting hardware, job site preparation, scaffold safety, fall restraints, etc.

Fig 2. Prep Work to Accept a Living Wall.

One type of man lift.

This is not to say this is the norm for all green wall installations.  In my personal experience, even the largest of landscape firms we have worked with globally do not have the knowhow, experience, and insurance coverage to conduct a large scale green wall installation over 20 feet high.  Yet, it is here I have to cross over the line and lean to the landscapers to rely upon for continuing maintenance procedures.  Pending the scope of work construction, contractors are the large scale installation experts, and the landscapers and growers are the plant experts who should, by all rights, also be the maintenance personal.

This raises the question about additional liabilities and working with extended heights.  May I remind you that the landscaper is not traditionally adapted to working on scaffolds or in a man lift (a machine that is like a boom that carries a person to an elevated height).  Green walls provide a new paradigm to the responsibility and job description of the landscape contractor.  This puts an even bigger burden on the manufacturers to ensure they provide resources for the maintenance technicians, requiring additional job safety training and new equipment training. There is a place for both the installing contractor and landscape contractor; having a company who can provide a single service is ideal.  Experience is a foundation to lean on as a consumer, and “New & Exciting” could potentially equate to “Dangerous & Liable.”

The second question that is always asked when I’m speaking or in conversation is, “What about the growing media?”  I always respond, What about it?  Fact is, for every company there is more than likely a different method or medium they
grow in.  I always use the word green wall loosely and remind people that "green wall" is an all-encompassing term.  And growing "media" is the plural of growing "medium," so unless you have more than one type of growing mix within a project, it should be referred to as growing "medium."  And when we're talking about growing media, there are two areas to distinguish between regarding placement in a green wall.

Left: Living Wall - Saul Nursery, Alpharetta, GA, Photo by Caroline Menetre.
Right: Green façade - Desert Ridge Marketplace, Phoenix, AZ  by Greenscreen;

If we're defining a green wall as a green façade, the growing medium would be found at the base of a 3-D trellis type structure to support climbing plant material and vines.  In this case you should have a growing medium that is rich in nutrients, drains well, and has a pH level to support the type of plant material in its particular location.

The Musée du quay Branly Hydroponic Living Wall by Patrick Blanc.

If we're defining a green wall as a living wall, that's a completely different story since there are multiple locations to place the growing media - or none at all.  Follow up questions are necessary!  So when someone asks me about the growing media used in green walls, first of all I have to politely ask if they're actually referring to a "living wall."  In confusion, the general public simply assumes because it's vertical, it's a living wall.  (You can read an archive of one of my earlier posts that clearly defines the differences between a green façade and a living wall.)  I've found that more often than not, the question is clearly directed towards a living wall.

To confuse matters worse, the ever popular work of French botanist and designer Patrick Blanc is defined as a true hydroponic living wall.  This means it does not contain any organic growing media; the plant roots are fed with circulating water containing nutrients.  The definition of a living wall states that the roots are evident throughout the entire wall, not just at the bottom as found in a green façade.  So, in this case, we have two types of living walls - one with a growing medium and one without.  Back to the question, What kind of growing media is used in living walls?

Before I answer the question, you have to understand plants require very few things, and aside from sunlight and the availability of water, free drainage is key - the growing medium has to provide the matrix to allow for water to flow freely in order to prevent root rot, promote oxygen uptake and microbial action.  Plants also need to have the ability to extend their root system - if you have ever purchased a plant where the roots are wound around the inside of a pot, you know that plant is root bound and would have eventually choked itself to death.  A hard clay type of soil would also restrict root development due to compaction and could eventually kill a plant by drowning it.

Sphagnum Moss Wrapped in Wire Mesh.

In addition to preparing the medium for plant roots, consider the plant requirements in relation to light, water and nutritional needs.  Other than the lighting, which allows for the plant to produce sugars for energy and growth, everything about your plant should evolve around the roots.  Using the correct composition of growing medium will strike a balance of air space, water and nutrients - if you have healthy roots you will have a healthy plant, and if you have healthy plants, you'll have a successful living wall.

Some of the new designs starting to emerge consist of a variety of wire meshes shaped into forms that contain a 3-D block of sphagnum moss, coir husk or rock wool.  Other bagged type systems use or have used anything from peat moss to potting soil to any of the above.  The hanging pocket types, or what I referred to earlier as minimal use, suggest employing “a high quality potting soil.”  So with three different types of systems, you may have three types of growing media and methods to establish the wall.  And not all growing media are equal.

Currently, there are a variety of mechanical means to hold plants on a wall, but I feel the greatest advances in green wall technology are going to be in the growth media field.  Rock wool, coco husk, and sphagnum mosses are all very porous and popular in the hydroponic arena.

Pros: They allow for drainage, root growth and are lightweight.  Cons: They need a constant supply of irrigation and fertilizers, artificial environment regulation (the need to always monitor the pH levels), and there is no beneficial microbial activity, especially around the roots of the plants.

Top View of a Coco Husk Insert.

On the other hand, quality potting soil mainly consists of peat moss; although controversial and questioned as being a sustainable harvesting practice since it involves older bog ecosystems, it provides the support matrix needed to sustain plant growth.  Media-based living walls were introduced around 2004, and the growing media used was a high quality potting mix.  Personally, peat was the base to one of our older medium recipes, with other added ingredients and micro-organisms, which I can’t disclose because of trade secrets.  So I know firsthand that the type and quality of peat is of the utmost importance.  A newer bog provides a more fibrous peat, which is ideal, allowing the final product to gather naturally to form something like the commercially available pre-casted peat pots. The fiber content in the higher quality media should be above 60%, have a high water retention rate, drain freely, and provide a balanced pH.

But the potting mix media also needed applications of periodic fertilizer. To add additional controversy almost ignored and rarely published, by comparison traditional lightweight extensive green roof media hold minimal nutrients because of the lack of organic material - and the result is the application of synthetic fertilizers to feed the plants. Even though low maintenance, most succulents and traditional sedum still need nitrogen (N), potassium (P), and phosphorous (K), in addition to micro nutrients as part of a fertilizing plan.

When chemicals are not being absorbed, they become part of the runoff in the traditional sense - the fertilizers are now making their way to the waterproofing layers of green roofs and washing into the combined sewers, drainage ditches and into our waterways, no different from fertilizing your lawn. The same is true for the living walls, no matter which growing media is present, fertilizer is going to have to be added and will eventually contribute to runoff.

Recently I became aware of a medium designed from a fermentation process using old shipping containers that is providing high quality fibrous compost with a consistent organic nitrogen content of 3% using chicken manure as the key ingredient.  (Chicken manure has been documented to leach into the water table causing harmful effects because of the concentration when not removed or used as a by-product.)  The end product results in a concentrated N, P, and K mix  enhanced with additional micronutrient rich media, while the process removes 100% of the methane off-gasses.

Fermentation process in old shipping containers.

The process creates a compost and bio-fertilizer being used as part of the new living wall growing media.  These properties provide a benefit for the green wall and roof market because it will eliminate the use of synthetic fertilizers and it will not leach like the synthetics.  There is no runoff so it becomes the organic base to the advanced living wall and roof media, and can be used as a top dressing to all green roofs to replenish the nutrient values.  For green walls, a tea comprised of the fermentation is introduced to the irrigation providing some of the highest quality of living
wall media available.

So, what is my answer to the ever popular question, “What about the growing media?”  Now you can see why I answer, “What about it?”

Green walls are advancing; the means in which we secure plants to the wall are numerous.  The novelty is over and living wall projects are taking on awe inspiring displays of art, function and controversy.  And questions of liability, construction, and maintenance are still part of the unknown equation.  I know that the skills of many trades are needed and the skill set
needed cannot be seen as a standalone trade.

I believe change is good and advanced technologies will continue to grow, and liability issues will decrease with increasing levels of education and experience.  I also believe that the next wave of fertilizer-free growing media for both walls and roofs is close to being commercialized.  No matter what, the industry has expediential room for growth and advancements, keeping us all busy for quite a while.

George Irwin, The Green Wall Editor

Empowerment with Vertical Agriculture, Edible Walls
& Urban Farming Food Chains

By George Irwin, The Green Wall Editor
Photos Courtesy George Irwin Unless Otherwise Noted
December 15, 2009

Author's Herb Wall

If you ever have an opportunity to talk with my family you'll see there are very few things I am obsessed with except for my fascination with food.  Fortunately when I am home and not traveling, I have the means to provide nutritious food such as fresh berries, raw vegetables and other non processed edibles.  I do 90% of the cooking; I make three meals a day for my family - breakfast before school, homemade lunches, and dinner.

For me it is not just about making the food - I am obsessed with cooking high quality nutritious meals that lack processed or frozen produce.  I’m talking specifically about not using frozen or canned vegetables and eating ripe juicy fruit.  I’ve been fortunate to be in the right place at the right time but during these trying financial times not everyone can afford fresh foods which provide the highest nutrition.

Fuel is at an all time high, the U.S. economy is hovering above an economic crash, houses are being foreclosed, unemployment is higher than ever and people still go to bed hungry.  Putting food on the table is one thing, being able to afford a high quality nutritious meal is another.  Yet I also know too many families who don’t cook such meals simply because it’s easier to stop at the local fast food store or to microwave a frozen meal.

I was part of a discussion group about Urban Agriculture the third week in October, 2009, in Toronto as part of the Cities Alive! World Green Roof Infrastructure Congress.  The theme was growing fresh produce in urban environments, and there were some great projects implemented on roof tops of inner cities, the use of abandon lots, and the concept of “Vertical Farming.”  Vertical farming is a breakthrough in socialized food production to help feed the ever growing populations.  It was hard to think in a conceptual manner when we were already implementing vertical farms as one of the most powerful applications of agriculture ever.  The concept of vertical farms is no longer conceptual!

Vertical Farm Concept from

Vertical farms are real, however, there are many concepts that still lend themselves to including horizontal growing as part of the vertical concept, yet this is not necessarily the case.  It only makes sense for this column to incorporate my love for food and my experience with Vertical Agriculture since I have been involved with what is no doubt one of the most incredible Vertical Farming projects to date; it’s called the Urban Farming Food Chain.

Living Walls - Left: Diagram from GLT; Right: Patrick Blanc’s mur végétal at Le Musée du Quai Branly;
Photo: Bill Bishop; Source: Human Flower Project.

Before I continue, let’s review the definition of “Living Wall” which has a root system throughout the entire wall within its mechanism in comparison to a “Green Façade,” better known as a 3D or wire trellis type, where the roots are at the bottom of the structure and it is the structure that supports the plants' climbing habits.  Due to the definitions, the walls of French botanist Patrick Blanc are defined as Living Walls even though they do not have a growth media base and are 100% hydroponic.

Author's Kids Planting Lettuce.

Back to my story - in 2005 we were preparing a test plot of plants with our products for the growing season, I was home with both my son and daughter who were 7 and 4 and wanted to plant something in the walls.  Here I was alone with two kids who wanted to literally play in the dirt, something we as adults forget to do, that is “play.”  My son found some old lettuce seeds in the garage and this is what they wanted to plant, but planting them in the ground was not good enough, they wanted to plant them in our Green Wall Modules (which eventually became the Green Living Wall Panels).

So we laid out two Green Living™ Wall Panels, filled them with growth media and my kids planted the seeds, painstakingly one at a time.  If you know anything about lettuce seeds they geminate pretty quickly.  A few days later my son discovered the germination and he made me hang them on the wall.  To my surprise, in less than a few weeks we had a full panel of lettuce that we used for our own salads.  This was the start of a revolution; that same summer we planted tomatoes, cucumbers and basil - we dubbed it the salad wall.  The following year we developed a 4 and 6 inch-depth green wall panel and were successful with zucchini, leeks, strawberries, herbs and baby sugar watermelons.  We had no idea what we were about to realize - we can grow almost any common crop literally in a vertical plane.

Our first Lettuce Wall

Two years later, I received a call from an architect, Robin Osler, whom we have worked with in the past.  To my excitement and curiosity, Robin asked me if we ever grew food in our walls.  Of course we had just been through two years of authentic research/self use using our Green Living Walls for growing food!  Robin introduced us to Joyce Lapinsky and Taja Sevele, the founders of an organization called Urban Farming (

Urban Farming’s mission is to eradicate hunger.  This was perfect timing since as a corporation we, too, were seeking a non-profit to adopt as part of our corporate giving program.  Social responsibility is a key value in our business plan and Urban Farming’s mission was very much parallel to what we believed in.  Urban Farming, based in Detroit, has its roots, no pun intended, in planting gardens throughout urban areas utilizing vacant land to help feed the homeless.  This land is not always available, sometimes contaminated, and simply not always accessible in urban environments.  However, there is always vertical space with walls.

Joyce, who is the West Coast developer for Urban Farming, asked me about a Green Living™ Wall growing food for the homeless in Los Angeles.  From here the Urban Farming Food Chain was born.  Robin associated the idea of a chain's having links and the links making up the chain with each edible wall being a link in the chain that would connect the Edible Walls around the world as part of the “Urban Farming Food Chain.”

Skid Row, Los Angeles, California.

Joyce and Candice (Candice was a volunteer helping Joyce in Los Angeles) had spent days and weeks looking for walls in the LA area, meeting with local officials and building owners to grant the use of such walls.  Joyce found four locations to install the Edible Walls, I flew to Los Angeles, and I had a chance to talk with the people we were trying to help.  Personally, I was in shock to experience the life of a homeless person; I was at the epicenter of homelessness, the skid row area, Gladys Park in the center of Los Angeles, 10 minutes away from Hollywood and millions of dollars of revenues being generated minutes from what seemed to be a scene in a movie.  I was feeling like an intruder, unwelcomed and at the same time experiencing guilt for my successes in relation to what I was experiencing.  I didn’t have to live in a box, fight for a bench, and felt my pride would never let me stand in line for food because I was starving.

Even among their life trials these people faced everyday there was still evidence of a hierarchy within the sub culture of homelessness.  The real estate may not belong to them legally, however, this area of street and park was their home.
Trying to put myself in their shoes, I was thinking that if I were homeless here how great would it be to have fresh food literally free for the picking.  One of the walls was going to be adjacent to a basketball court.  The initial mistake we assumed was that the Edible Wall was something they wanted; yet we were met with resistance.  In the hierarchy of the residence of this particular park, we were treading on something that was not ours.  We had to actually step back and re-think our approach; we had assumed that the edible wall, a food providing wall with strawberries, cucumbers and more, would be accepted with open arms.

No different from you and I, very few people in this world enjoy having something forced on them.  If we would have taken the time to do preliminary interviews and engage the people we were trying to help, I think the initial outcome would have been more accepted.  Homeless or not these people, this society, clan, whatever they are labeled, still had feelings and a sense of ownership of the space we wanted to use for their benefit.  We had seen it as helping, and they had seen it as intrusive and “How dare you tell us what we want!”

Edible Wall Growing at Cal Poly Parking Area.

Joyce and Candice eventually found four locations to accept 750 square feet of the Edible Walls.  This project would be the first of its kind anywhere in the world.  The concept was to be able to allow anyone to walk up to the wall and harvest produce and eat it raw.  We wanted to bring the first walls to the sites already bearing fruit, but implementation was much more difficult than just hanging up our wall systems.  We had to start the growing and where?  We had to have the panels delivered and installed, teach maintenance, irrigation, and designate someone to be responsible for each project.  Logistically these edible walls are unlike a sedum green roof in that they need much more water, trimming, harvesting, and are located on a wall in downtown Los Angeles - this was the hardest planning project for our team and all with minimal funding.

The first recruit was Hunter Francis from California Polytechnic Institute (Cal Poly) in San Luis Obispo.  Hunter and two graduate students were willing to turn one of the parking areas into a place to grow the Green Living Walls prior to installation.  If you recall, my kids started planting seeds and to this day we still plant some seeds on the walls, however, it works best by starting with a 1” plug or starter plant.  So the wall units were laid out in the parking area, filled with specialized growing media and planted with a combination of seeds and starter plugs.  The panels were allowed to mature for six weeks and in August, 2007 we had 15 volunteers to help load the panels in two refrigerated trucks driven and donated by another local produce delivery company to downtown LA.

Left: Homeless Participation; Right: Unloading the Truck.

Two trucks went to four difference locations; it was very early in the morning and tight moving the 18 wheelers around in the Los Angeles morning traffic.  And getting to the walls was a difficult task because of the distance between the delivery truck and the mounting surface.  For example, at Miguel Contreras High School we had to walk the panels almost 400 yards to the wall.   At the Los Angeles Food Bank we had some of the workers help us unload the wall and the final two destinations, Rainbow Housing Trust and The Weingart Center - literally the center of homelessness - held the best surprises and provided the start of an advanced education program.

Volunteers helping with a green, living, wall.

The truck pulled up and a crowd started to gather out of curiosity; the crowds were the same people we were helping. Many volunteers started to unload the panels and the people in the crowd, without asking, simply jumped right in and helped us unload.  The senses of pride, self worth, and empowerment are words I used to describe what they were feeling. One participant told me, “It isn’t everyday a truck pulls up with fresh tomatoes to be hung on a wall.  So many times people help me and this time I want to help someone else.”

As the panels were unloaded and the crowd diminished there were four participants who stayed with us.  They expressed how they wanted to see these tomatoes on the wall so I personally invited them to help.  They worked with us for the first half of the day and asked if they could stay and come back the next day.  This was a welcomed surprise - as a former teacher I am very much for hands-on learning and when someone asks to be taught or expresses interest in something you don’t say no.  That night I asked our installers if they minded that they remain on call vs. installing the four walls.  Of course they didn’t because they, too, were volunteers.

Left: A blank wall in July, 2008; Right: Afterwards, a lush Edible Wall just a few days later at Skid Row Housing Trust's 'The Rainbow' Green Wall thanks to the Urban Farming Food Chain and volunteers.

A friend of ours from New York, Kevin Kaye, and I worked with and taught these four individuals from sun up to sun down for five days.  They learned everything we could teach them from start to finish; eventually they installed the last wall without our help, including the irrigation.  They were not the only ones who learned something that week.  We found out that these were people are no different than we are.  One had been a film editor for Hollywood, another a contractor, the third a business owner and the fourth a union carpenter.  I thought in silence to myself, “What and where did things go wrong to the point they became homeless”?  It taught me not to judge; I would have assumed that it was due to drug addictions, laziness, or a life changing disaster.  For me the stigma was gone, these were no longer homeless people; they were our neighbors and peers and now my friends who only had a bad situation get out of control.

Los Angeles Food Bank: Tomatoes, Leeks, Strawberries, Cucumbers & More.

You may ask why I was the one installing these walls in the first place?  We did have “installers” and they could have done the work and that would have been the end of it.  Our company is well rooted in moral values.  No one can ever come to us asking for a check as a donation, the answer would be no.  But if you want our help, we will provide you our hand and sweat equity, money only goes so far and who knows where it goes.  What we experience as corporate giving allows us to learn just as much as these four homeless people did during that week in August.  This is social responsibility at its best, I’m no religious man but I do believe in teaching someone to fish so they can feed themselves instead of providing a hand out.

Left: Celery in the wall; Right: Sponsorship recognition at the The Weingart Center.

What we have done is produce a foundation that has provided a life changing educational opportunity while providing high quality food in environments that were at one time at the mercy of the distribution from a traditional farm.  Now instead of empty buildings and abandoned parking areas there is the tangible and real application of an Urban Farm, future educational opportunities, job creation and it’s all done without specialized plastics, pumps, electricity, excessive water or fertilizers.

Left: Volunteers and me; Right: Enjoying a beautiful new Edible Wall.

Volunteers celebrating a completed Urban Farming Food Chain Green Wall in Los Angeles.

This is Vertical Farming changing the way we think about agriculture and the relationship to urban inner cities. If these four individuals were to be paid for their work there is a labor value of close to $55.00 per man hour to install these walls and another $20.00 per man hour to maintain them and an additional income opportunity by selling the produce at road side stands in center city less than 100 feet from where it was grown.

It doesn’t end here; this was a wake up to a much larger calling.  What if we can take what we have done and duplicate it throughout the world? We can and did with easy to use, almost off the shelf raw materials.  What we did is scalable, affordable, and does not require specialized equipment.  The Urban Farming Food Chain also provides additional learning opportunities to learn how to cook the food, prepare healthy meals, job training and more.

"A" Frame Vertical Gardening by GLT.

This experience has spawned an agricultural revolution - vertical farming is no longer conceptual and the use of horizontal space is not necessary to grow food.  This technique of vertical farming method food production uses the power of nature, traditional soils and is done 100% organic without the use of chemicals and pesticides.  In just the past year, products such as the Patent Pending Green Living™ Technologies “A” Frame are now available to grow 96 sf of food while utilizing only 32 sf of minimal horizontal space, doubling and tripling the yields per square foot and all in a parking lot or in a rehabilitated building.

Our relationship with Urban Farming has become a staple of our business model for many years to come.  We continue to work towards developing new agricultural techniques, self help programs and empowerment opportunities not just for the homeless but for ourselves.  There is much more to businesses than writing a check as a giving program.  It’s been a humbling experience to be able to impact so many in such a short amount of time.  I suggest everyone go out and volunteer your time, as you, too, may learn something.

George Irwin, The Green Wall Editor

Sponsor Recognition


Since the installation of the first Urban Farming Food Chain in Los Angeles, there have been Edible Walls implemented in more locations such as New York, California, Vancouver, B.C., and Hawaii with others slated for South Africa, South America and Dubai.

Currently in progress, Green Living Technologies has developed the GLT Innovations, LLC which includes the GLT Institute providing green job training and job placement in the future GLT Food Factories and GLT Farms, all utilizing the Green Living Technologies Green Living Walls.

If you’re interested in sponsoring a link in the Urban Farming Food Chain, please contact


Green Walls as Marketing Trends in 2009
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin, unless noted
August 3, 2009

No different than 2008, this has been a very busy first half of the year with expos, workshops and conferences.  The build up for  Green Roofs for Healthy Cities' Greening Rooftops for Sustainable Communities Conference, Awards and Trade Show is always great, and to name just a few coming up in the fall there are the American Society of Landscape Architects (ASLA) Annual Meeting & Expo in Chicago, the World Green Roof Conference in Toronto, and Greenbuild in Phoenix, not to mention the thousands of other industry awards and trade shows held globally.

What about the non-green roof/wall industry shows?  Food, vitamins, fitness, cleaning products, cars and thousands of other companies trying to establish symbiotic relationships to being green or those going green are out there promoting, selling and engineering how to gain market share.  And how are  companies attracting attention?  What are they doing differently to draw you in?  Here are some of the albeit eye-catching but less creative ideas I have seen - how about that loud blower with the tube that goes 20 feet in the air and waves frantically?  Or the small flashing button someone wears on their jacket to make you look or the obnoxious strobe light.

My personal favorite “made you look” ploy is the glamorous women at trade shows who have no idea what product they are promoting.  On a larger scale I am impressed with the jumbo TV screens that have taken the place of the common billboard and Times Square in New York City has everything from a scrolling news cast, bright lights, giant bottle caps to animated branding.  What does all of this have in common?  Marketing.  Doing things bigger and better and in a way that has never done before.

Marketing includes branding, consumer awareness, client relationships, pricing and more; this is nothing new, it’s a multi – billion dollar industry.  I found the formal definition of ‘Marketing’ via Wikipedia to contain a minimum of four definitions from just as many chartered institutes and marketing associations that included everything from advertising, selling, distribution, research, social sciences, sociology, math, pre and post sale promotions……and more I won’t list as it’s simply too long….UGH!  Time out!  I just want a simple definition, yet apparently there is no such thing.

From personal experiences there are many newer marketing tools like the ever popular email newsletter, blogs, Twitter, etc., which are all great for electronic interactions.  But in our real, physical world, what about the higher end signage and branding?  With the economic downturn and as tough as it may be financially, the experts say to increase your marketing budget instead of cutting it.

Starbucks in Seattle; Photo:

According to guerrilla-marketing expert Jay Conrad Levinson, "In times like this, people think the first thing to do is to cut back on marketing to save money, but that's kind of like ditching your wristwatch to save time.  A down economy is not a time to become low profile, or people will forget you."

The new wave in marketing and the trend we are seeing now is through green walls, both permanent and temporary.  Big business is recognizing the marketing potential not just to attract attention, but to attract positive attention to their products and services.  In a very early post I once coined green walls as “Marketing Genius.”  Now if I could only predict the stock market like I did green walls.

Green walls initially focus on visual marketing (wait until the next few paragraphs).  Vision is one of the primary human senses and the patterns we recognize to differentiate the world around us become familiar until something new or unusual interrupts the visual landscape.  Visual marketing means to kick it up a notch and break up these stale vistas.

This may include seeing the combination of letters and words making up this very article or the same buildings and scenery while traveling to work.  You’re putting ordinary symbols together that are very familiar and, for the most part, can become a blur of sameness.  Case in point, the font and color for this piece are very common, but add the following “green wall” in all caps with bold font and a different color, and it draws attention even before you can get to it: “GREEN WALL

Left: Before, common façade;
After: 2,400 sf of vertical wall (coming in September, 2009 at 1 PNC Plaza, Pittsburgh, PA).

The same is true as we visually scan a room, office, cityscape, etc.  There is a common psychological expectation and response for what are used to seeing vs. seeing something unexpected.  Over the winter I was at the National Restaurant Show in Chicago and this became abundantly clear.  Being involved with the green industry it has been common for me to see nursery people, green roofs and plants all together in one room, but the restaurant show was a contrast.  It showcased lot of industrial, metal equipment and accessories, everything from shiny stainless steel counters and coolers to copper cooking pans and cutlery.

Speaking of contrasts, amongst all the inanimate stainless steel there was one great contrast which really stood out, a living booth.  A company created a leafy green indoor paradise by utilizing green walls and sod floors very different to the rest of the show!  The booth was actually promoting awareness on how restaurants can go green and so they used highly textural live plants in juxtaposition of the other cool, smooth surfaces.  The point is the booth was extremely unique and so distinct that people remembered it.

Contrasting Booths at the National Restaurant Show 2009.

Using green walls is a tool that gains attention - add a brand to it and the experience is now even more memorable.  In fact, for 2009 the Publisher and Design Editor for included Living Billboards in the #10 category, Client-Specific Boutique Greenroofs, for their yearly installment of the Top 10 Hot Design Trends in Greenroof Design:

Living Billboard: "Garden Spots," New York City, 2008. This award winning design proposes to create living “air gardens” on the unused backsides of New York City billboards. The design team from TODO Design and DAS Studios won first place in the iDA Land & Sea Competition for their unique approach to greening the city. Very eye-catching!

Living Billboard: "Billboards Made of Lettuce," 2008. This unique growing outdoor garden billboard was planted with green lettuce planted to form the words “fresh salads” by Leo Burnett. It promotes McDonald’s health-conscious menu items and won Gold at the 2008 New York Festivals’ Innovative Advertising Awards.

I said green walls initially focus on the visual, but that is not always true.  Vision is not our only sense!  Touch and smell are two other very strong senses.  I have seen people walk up to large commercial projects and small trade show walls touching and asking if it was real.  Texture and smell are as relevant to the overall project or marketing as the aesthetics. Texture is used to create pictures and logos within the walls.  Remember the contrasting description between the living booth and the stainless steel?  The same is true for custom branding embedded directly into the wall itself, adding an entirely new dimension and contrast that breaks up normal visual patterns.

Getting all the attention at the Eastview Mall, Rochester NY

Tabletop Green Wall w/ Basil

Don’t think for a second that marketing stops here, though.  Scent marketing is a science by itself.  A classic example is for home sellers to bake cookies when potential buyers visit to enhance the sense of a cozy home. Going back to restaurants, how about walking into an Italian restaurant and the first thing you’re greeted by is a fresh face full of basil…growing on the wall.

Maybe Italian is not your preferred choice.  Then how about lemon grass, sage, chives, mint or just about any scented herb?  All growing on the wall.  I know chefs who greet clients at their table,  turn to trim a fresh herb from the green wall in the dining area and then freshly dress up the customer’s meal.  How about serving dessert with the mint garnish literally trimmed from a mini-herb wall right from your table?  I think it would be safe to say this would be a dining experience with a personal twist to come back and enjoy again.  And why stop with restaurants?  How about a relaxing spa massage with humidity-infused, freshly snipped lavender or mint from a green wall?  These are true fresh scents through natural air fresheners and aromatherapies with no Volatile Organic Compounds (VOC’s) from artificial sprays and misters or those little plug-in “fresh” scents.

Unlike many green roofs, you can see a green wall up close, and green walls scream attention.  No matter what the intention is, marketing, function or environmental, the fact is there is much more to green wall marketing than just a cool trend, and we’re just seeing the beginning of their possibilities in the advertising marketplace.

Marketing for a marketing firm in a memorable Seattle lobby.

George Irwin, The Green Wall Editor

Green Wall Research, Full Steam Ahead!
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin
April 11, 2009
Updated April 26, 2009

The reduction of urban heat islands, usage of fossil fuels, increased storm water retention……..sound familiar?  If you’re a green roof fan you will recognize these are some of the benefits of green roofs.  Green roof data has a long history.  What about green walls?  Some of the earliest research depicts the use of green façades as a means to cool buildings by shading.

In reality it was the grape that was planted close to the building.  The vine produced more fruit faster, it ripened with added sweetness and produced an excellent wine with high alcohol content. With a long history of facades, where is the modern data?  More scientific research is being done as I write.  For example, Green Roofs for Healthy Cities announced a formal research fund at the 2008 Greening Rooftops for Sustainable Communities Conference, Awards and Trade Show in Baltimore.  I know of a few others that are more specific to individual manufacturers.  With all the available data on green roofs, green walls are lacking.

Some of you may recall a study published by Drs. Brad Bass and Bas Baskaran titled “Evaluating Rooftop and Vertical Gardens as an Adaption Strategy for Urban Areas,” (2003).  In this column I include some of the paper as a pre-cursor that identifies green walls and their ability to cool the walls of buildings.  Involved directly with many research opportunities, I find the common question is relating green walls to green roofs.  How can green walls compare to green roofs in saving energy?  Here are some of the earliest modern references to green walls that are compared to preliminary short term data that will provide the ground work for additional long term studies.

According to Bass and Baskaran, "Higher than average temperatures within city limits known as Urban Heat Islands (UHI) are a direct result of replacing vegetation with typical urban surfaces also creates an elevation of temperature relative to the surrounding rural or natural areas.  The UHI occurs because more of the incoming solar radiation is absorbed by dark surfaces such as rooftops and pavement in the city and reradiated as longwave radiation or heat.

Green Roof Data Collection

"Below a certain temperature, the demand for electricity is inelastic.  Above this threshold, every degree C increase can increase electricity consumption by 5%, increasing emissions of the fossil fuels required for its generation.  Although the UHI may be as small as 2° C, that may be sufficient to move the temperatures above this threshold due the additional demand for air conditioning and requirements for refrigeration.  The increased temperatures also increase the problems associated with heat stress and the rate of ozone formation."

Vegetation can reduce all of these impacts.  The focus is vegetation reducing the UHI and thermal elevations is because of evapotranspiration. Incoming solar energy that is used for evapotranspiration cannot be absorbed and re-radiated as heat. Studies in Oregon demonstrated that non-vegetated areas could exceed temperatures of 50° C (122° F) in July while vegetated areas remain at 25° C (77° F) (Luvall and Holbo, 1989).

Vegetation can also further alleviate air and water quality problems by filtering pollutants through the leaves or the roots.  In addition, vegetation in urban areas has been shown to increase mental well being, biodiversity and residential property values.

"Most discussions of the UHI focus on the temperatures of surfaces or the canopy level UHI, which occurs at the level at which most people live.  We only feel surface temperatures directly when in contact with these surfaces, but they heat up the surrounding atmosphere.  For the canopy level, the primary affect is experienced in the evening.  Heat from rooftops affects the temperature of the boundary layer or upper layer of the atmosphere, the layer of the atmosphere extending roughly from rooftop level up to the level where the urban influence is no longer ”felt"" (Oke, 1976).  This additional heating occurs throughout the day and influences the chemistry of air pollution and temperatures above the roof."

Nakamura and Oke (1988) found that temperatures in the urban canyon and temperatures in the lower part of the urban boundary layer, are usually very similar.  Thus, higher temperatures above the roofs can affect temperatures at canopy level, where we live, and in areas with only one or two story buildings, the roofs may be at the canopy level.

"Reducing the rooftop temperatures would further reduce the use of energy for space conditioning in both the summer and the winter.  In the summer, a typical insulated, gravel-covered rooftop temperature can vary between 60° C (140° F) and 80° C (176° F) (Peck et al., 1999).  These temperatures increase the cooling load on a building in two ways.  Since the internal temperature underneath the roof is typically lower than the temperature above the roof, the heat will always flow through the roof into the building.  In addition, modern high-rise buildings are constantly exchanging the internal and external air.  Because of the high roof temperatures, the temperature of this external air that is brought into the building’s ventilation system may be warmer than the ambient air, requiring additional energy for cooling.

"Evapotranspiration from rooftop vegetation could cool the roof, reducing the amount of heat flow into the building through the roof.  The lower rooftop temperature would also reduce the temperature of the external air that is exchanged with the building’s air.  The temperature of this air could also be reduced if the rooftop garden is designed so as to shade the intake valves."  Summer temperatures as low as 25° C (77° F) have been observed. (Peck et al., 1999).

Most of the above is taken from the publication of Bass and Baskaran, and some of the data is well over 10 years old.  Ten years later the technologies, materials, and design techniques have also evolved.  There has been no slowing down the green roof momentum and green walls are not far behind.  The focus to combat the issue of UHI was primarily on green roofs until additional technologies were also being recognized for the ability to cool the Urban Heat Island.  The walls are heating up and reflecting UV rays just as much as a roof top, depending upon the color and surface material, location, etc.  Green façades (trellis structures with climbing plants) were utilized to shade the sides of buildings much in the same manner green roofs were used for the roof tops.

Here's the catch: on average buildings have much higher wall-to-roof ratios in most cases.

An even greater amount of space for vegetation may be available on the exterior walls of the buildings in urban areas, and growing vegetation on walls could create vertical gardens.  Vertical gardens increase the amount of vegetative surface in urban areas, increasing evapotranspiration and evaporative cooling, and can be used for direct shading as well.  In comparison, green roofs directly affect the boundary layer UHI, and vertical gardens can reduce the canopy level UHI.

Previous observations indicate that vertical gardens do reduce the heat flow into the building, and their surface temperature is lower than a bare wall, which is necessary to reduce the urban heat island (Bass and Baskaran, 2003).  A series of experiments in Japan suggested that vines could reduce the temperature of a veranda with a southwestern exposure (Hoyano, 1988).  Vines were effective at reducing the surface temperature of a wall.  In Germany, the vertical garden surface temperature was 10° C (18° F) cooler than a bare wall when observed at 1:30 p.m. in September (Wilmers, 1988).   The study does not state how mature the plants were.  Theoretically speaking, the potential for additional shading would be accomplished with with fully grown plants.

Holm (1989), demonstrated a reduction of 2.6° C (4.7° F) behind the vegetated panel.  For a building consisting of two 10mm fiber-cement sheets with 38mm of fiberglass insulation, a computer simulation estimated that a vertical garden reduced summer daytime temperatures on the surface by 5° C (9° F).  These results are not as dramatic as the cooling effect on a horizontal surface, such as a roof, but given the amount of wall space in urban areas, the potential impact of vertical gardening is expected to be quite dramatic.

These results were utilizing green façades and the primary method of cooling was shade and the process of transpiration accounting for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves.  Mentioned earlier were two ways of cooling a roof top.  The first is shading with vegetated coverage and the second is through the process of evapotranspiration to dissipate accumulated heat energy.  Technical breakthroughs have a few companies manufacturing and producing Green Living Walls or Living Walls - defined as wall structures that support rooted plant coverage. This is different than a green façade that can be identified as having a climbing plant at the base of a support structure. The majority of living walls are media-based except for a single hydroponic wall. The premise is that the media will also retain water available for evapotranspiration. Utilizing the living wall, both shading and evapotranspiration are implemented.

Many models exist that analyze numerous variables to determine the rate at which water evaporates and creates a cooling effect.  Let's keep it simple and provide tangible examples.  Since we established that vertical surfaces can be comparable to horizontal roof tops, can we assume a living wall with the same depth will provide the same cooling results, only vertically?

I would have to say "yes" as I leave myself open to debate and welcome other opinions.  Unlike green roof research, there is a lack of defining green wall data.  Green Roofs for Healthy Cities has implemented a research program for living walls and green facades. I have implemented thermal testing specifically for green living walls and will be analyzing data after completion of a 1-year study (July 2009).

The preliminary short-term thermal testing showed that a 3” (7.6 cm) deep green living wall provides similar results under the same environmental variables as a green roof with 3” growing medium depth.  The initial test plot was painted black (behind the living wall) to match the EPDM rubber membrane.

The preliminary short-term thermal testing showed that a 3” deep green living wall provides similar results under the same environmental variables as a green roof with 3” growing medium depth. The initial test plot was painted black (behind the living wall) to match the EPDM rubber membrane.

Preliminary Temperature Comparison Test Results

The preliminary testing shows an average surface temperature difference of 75° F (41.7° C) between the exposed rubber roof and the protected green living wall. This observation supports more advanced research. With more detailed testing and longer trials comparing 3", 4" and 6" rooting depths, I feel confident that the findings will show even better data as a direct result of evapotranspiration and shading.  The mentioned preliminary study is being conducted in Rochester, NY with a short cooling season.  This study will be compared to other thermal testing I will be conducting over the summer 2009 near Miami, FL, where we expect the green wall’s cooling capabilities to rival that of green roofs in locations with cooler growing seasons.

Recall Hoyano, Wilmers, and Holm had recorded 10° C, 2.6° C, and 5° C reductions in surface wall temperature utilizing green facades with shading as the primary means of temperature reduction.  Our initial observations indicate similar thermal mitigation by green walls compared to green roofs.

Why?  I hypothesize that medium depth, hydration layer, and rate of evapotranspiration each contribute to reduced wall surface heating.  However, the extent of these and other influences remain an open question until ongoing and future research can provide much needed data.  The eventual comparison will be between green façades and living walls.

George Irwin, The Green Wall Editor

Literature Cited:

Bass, B. and B. Baskaran, 2003: Evaluating Rooftop and Vertical Gardens as an Adaption Strategy for Urban Areas: Impacts and Evaluations Progress Report. April 1, 1999 – March 3, 2001.

Holm, D., 1989: Thermal improvement by means of leaf cover on external walls - a simulation model. Energy and Buildings, 14:19-30.

Luvall, J.C., and H. R. Holbo, 1989: Measurements of short-term thermal responses of coniferous forest canopies using thermal scanner data. Remote Sensing of Environment, 27:1-10.

Oke, T.R., 1976: The distinction between canopy and boundary layer urban heat islands. Atmosphere, 14: 268-277.

Nakamura, Y. and T. R. Oke, 1988: "Wind, temperature and stability conditions in an E-W oriented urban canyon," Atmospheric Environment, 22:2691-2700.

Hoyano, A., 1988: Climatological uses of plants for solar control and the effects on the thermal environment of a building. Energy Buildings, 11:181-199.

Wilmers, F., 1988: Green for amelioration of urban climate. Energy and Buildings, 11:288-299.

Note:  See the Baskaran, Bas and Bass, Brad (2003) "Evaluating Rooftop and Vertical Gardens as an Adaption Strategy for Urban Areas,” References Page listed at the National Research Council Canada - Conseil national de recherches Canada (NRC-CNRC) page.

Green Walls and Indoor Air Quality
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin, unless noted
January 19, 2009

Compare this wall to the one below!

What a relief it was to escape inside a friendly tropical office from the mounds of snow we have here in the Northeast and see lush green vegetation protruding from a wall deep into the long hallway.

It seemed as if it were a mirage as I walked closer to the wall, as a feeling of warm and moist air filled the corridor, removing my thoughts of the extreme cold outside back home.  If you’re lucky enough to live in a moderate climate during the harsh northern winters, you will more than likely have to endure a rainy season, but at least it’s warm.

This is exactly what happened to me after a visit to San Pedro Sula in Honduras a few weeks ago - the moist humid air was a welcome relief from the dry cold winter of the Northeast.

Green Living™ Wall in Tropical Honduras;
Photo Provided by Techos Verdes

Sick Building Syndrome and Indoor Air Quality

In the early and mid 1900's, building ventilation standards called for 15 cubic feet per minute of outside air for each building occupant primarily to remove body odors.

Back to reality, I’m from Rochester, New York, and we are currently buried in snow and cold.  The wall I was standing next to in Honduras offered a reprieve from the reality of the weather outside.  During all seasons, occupants inside offices and homes alike are suffering from dry air - from cracking skin to coughing and congestion from people with whom we share the space.  Actually, these are some common symptoms described by the U.S. Environmental Protection Agency which are indicators of Sick Building Syndrome (SBS).  Other more severe indicators include: dizziness and nausea; difficulty in concentrating; fatigue; and sensitivity to odors. 1

What causes SBS and how can adding green walls help?  The costs and potential payback are detailed in this article for the commercial property owner, designer, or architect who will be able to utilize this to inform clients.

Multiple sources contribute SBS to having a direct relationship with indoor air quality (IAQ).  Buildings, especially newer construction, are built to be air tight to provide a comforting environment with heat and air conditioning.  The adverse result is the lack of air circulation and proper filtration.  Inadequate ventilation is also a result of HVAC equipment that is either outdated or lacks sufficient means to distribute air.  The following are deemed by the EPA as the leading causes of SBS: inadequate ventilation; chemical contaminants from indoor sources; chemical contaminants from outdoor sources; and biological contaminants. 2

Solutions and Economic Considerations of Air Quality

The solutions to remove the compounds may include pollutant source removal or modification, an effective approach when sources are known and control is feasible.  Examples include routine maintenance of HVAC systems, e.g., periodic cleaning or replacement of filters, and increasing ventilation rates by utilizing HVAC systems, at a minimum, to meet ventilation standards in local building codes.  However, many systems are not operated or maintained to ensure that these design ventilation rates are provided.  Air cleaning can be a useful adjunct to source control and ventilation but has certain limitations.

Indoor Green Living™ Wall Freestanding Unit with VOC removing Peace Lily, Janet Craig, Pothos & Dracaena.

Particle control devices such as the typical furnace filter are inexpensive but do not effectively capture small particles; high performance air filters capture the smaller, respirable particles but are relatively expensive to install and operate.  Mechanical filters do not remove gaseous pollutants.  Some specific gaseous pollutants may be removed by adsorbent beds, but these devices can be expensive and require frequent replacement of the adsorbent material.  In summary, air cleaners can be useful, but have limited application and can be expensive.  According to the EPA, clearly the mechanical means of removing toxins, particles, and Volatile Organic Compounds (VOC’s) from buildings are options, but none claim to be the solution or 100% effective and are costly.

Natural Filtration

However, there is strong evidence on a more natural solution.  This natural or holistic approach to cleaning indoor air can be as simple as adding the ecosystem that is responsible for creating fresh air to begin with: the indoor green wall.  The  indoor green wall eco-system is a very complex order that has the ability to change; it’s a built in survival mechanism. Plants can be resilient and what may be toxic to one species is a source of survival for another.  VOC’s have been the focus of many studies in recent years and it is now evident that data concludes over 80% of VOC’s can be removed by plants. 3

Interior Green Wall; Photo Courtesy Elevated Landscape Technologies

NASA (1984) published one of the first studies demonstrating that plants can help to remove VOCs from sealed indoor environments (Wolverton, n.d.). 4  Later researches confirmed these findings and also suggested that micro-organisms of the soil might also be involved in removing toxic VOCs.  Certain plant species can remove up to 100% of the air-borne VOCs within a 24 hour period.  Some of the top performing plants include: Howea forsteriana (Kentia palm); Spathiphyllum wallisii var. Petite (Peace Lily); and Dracaena deremensis var. Janet Craig (Janet Craig Dracaena), (Burchett et al, 2001).  Most recently (March 2005), The Plants and Environmental Quality Group at the University of Technology in Sydney concluded that both the plant metabolism and the soil microorganisms are involved in removing the VOCs from the air. 5

Prior to the University of Technology (Sydney), other studies were conducted in controlled laboratory test chambers.  In an authentic setting the findings showed that plants work to remove VOC’s in a real life situation.  The data demonstrated that both floor and table specimens, in air conditioned and non-air conditioned space, were effective in reducing the VOC’s to ~100 ppb (parts per billion) - regarded as acceptable using only 3 - 6 specimens in 10” and 12” pots.

Green Wall at the University of Guelph-Humber in Toronto

So it's obvious that if you are considering adding vegetation, plants or a green wall in your building you don’t have to have an interior jungle and masses of plants to obtain results.  Conclusions of both the field study and controlled studies strengthen the conclusion that “The potted plant microcosm is an effective, self regulating indoor-air-cleaning-system for ‘bioremediation of indoor air or phytoremediation of indoor air quality," (Burchett et al, 2005).  The plants are also self regulating; they automatically kick on when the VOC levels reach 100 ppb. 6

We know that cleaning the air can be done mechanically and biologically.  The mechanical means would need to include at times cumbersome and costly equipment,  require additional space, potentially cause an acoustic burden on the immediate work or living space, and may not prove to be 100% effective.  The mechanical means provides one service without any additional benefits.

Let's premise that the data is a direct reflection on using a soil-based potted plant; in theory then it is assumed that for comparing green wall systems, a soil-based green wall would need to be considered for similar performance.  The data suggests that the VOC’s removed are a direct result from microbial reactions at the root level.  Biological means of adding plants has proven to rid the interior space of VOC’s to an acceptable level.  Adding plants also offers other benefits that include aesthetics, raising humidity levels to the air during the dry seasonal months, and they also offer opportunities of marketing value.

Commercial Floor Space Comes at a Premium

The studies from the University of Technology used specimens of table and floor units / potted plants containing Janet Craig Dracaena (Dracaena dermensis).  The study needed to utilize valuable floor space to house the pots.  In the United States, on average retail and office space is $25.50 per sf (New York City averages $38.00 per sf as a high and Iowa averages $13.60 per sf as a low)  7.  Allowing for an area of sufficient floor space that would create the desired results of cleansing the air of VOC’s and provide an aesthetic value would require six potted plants @ 10” – 12“ deep, or the equivalent of 35 square feet.

6 – 12” Potted Plants, Figure 1

From a monetary perspective, due to its vertical nature a green wall is less than half the cost of occupying any retail floor space, assuming the cost per sf in rent noted above is accurate.  One retail store and green wall owner recently said:

“I’m reluctant to find the money to spend on plants that take up floor space in our retail store when I would rather have merchandise; it’s just simple economics.  Since we installed our green wall not only has our store been noticed but the area has been more inviting and the comments from our customers have been nothing but positive.” ~ Joe Edmond, owner of Green Acres Garden Center in Greece, NY.

Floor vs. Wall Space: Get More for Your Money

The value of implementing such an arrangement would equate to sacrificing a conservative 35 sf of floor space x $25.50 per sf would require a monetary expenditure of $892.50 a month on potential floor space that could be otherwise be dedicated to another desk or, in a retail space, more merchandise on the floor.  Looking at the long term expense based on a yearly value, $892.50 per month for floor space x 12 months is $10,710.00 per year for an aesthetically pleasing and functional area of potted plants . (*For the purpose of this column the cost of plant maintenance and other utilities were not considered and the figures mentioned are generalized as a base line comparison to evaluate other budgetary options.)

The current market for an indoor green wall has increased to rival that of an exterior wall.  The cost per sf has ranged from $100.00 to $175.00 per sf depending upon the system and the plant material.  Based on our estimated yearly cost to allocate 35 sf of floor space containing potted plant material, a more economical option would be to consider a green wall. Utilizing the simplest of green wall systems and the lowest of initial cost per square foot, the wall could be as low as $3,500 for the same 35 square feet of floor space.

Figure 2

Now, in reality that original floor space of 35 sf was not 35 sf of complete “Green Vegetation” primarily due to the voids of the potted plants.  (See Fig. 2)  The green wall, however, would provide a canopy that is 100% equal to that of the design. That same 35 sf of floor space on a wall is actually 35 sf of “Green Vegetation.”  There are no voids and in theory as an owner of the green wall the air cleaning and VOC removing benefits, according to the previous data, would provide an even more effective return on the investment - strictly speaking about the green area you would get more “Green Vegetation” for your investment.

More Tangible Benefits

On a lesser note, other opportunities present themselves as tenants, clients and other building visitors with green walls extend comments like, “I wish there was more of these plants,” “Cool,” “Are they real?”, “The room smells so much better,” “What a relief from the cubicles!”  The result is people are talking and presenting an opportunity to reflect positively about the new green space.  After installing a green wall, one major retailer had increased traffic due to the attention resulting in higher margins.  Other tangible benefits include noise reduction, improved productivity and lower absenteeism, to name a few.  According to Environmental Building News, a return on investing in plants would result in an annual savings of $975.00 per employee, a return on investment of 995%. 8

Environmental Building News, Vol. 13, No. 10; Figure 3

Green wall design and planning require mechanical functions as well as biological.  As a designer, one of the key components to consider is how the wall will be irrigated.  This is the number one evaluation, not any less important than the lighting, maintenance and system type but if the wall is to include an automatic irrigation system from a constant source of water (a direct connection to a main water line), we strongly recommend an overflow built into the irrigation catch basin.  To no fault of any one system or any system installer, if there is a mechanical failure within the irrigation components the water will be diverted into the overflow preventing any flooding.  Another option is to have a reservoir of irrigation simply re-circulated throughout the wall.  The best advice is to talk to the system manufacturer or installer about your irrigation options.

In previous articles I have written about various green wall systems, definitions and applications.  I’m going to premise a topic that I will eventually write about at a later date, but currently we see an opportunity to integrate mechanical and biological means of using green walls as a bio-filter.  When designing a green wall as integration into the building there is much less of a chance for the system to be value-engineered from the project.  Design the wall as a part of the building and the building's ventilation system is a must-have not just for aesthetics, but for overall functionality purposes.

Beauty and Function

Green Living™ Walls are beautiful living machines.

At first, it is always the breathtaking beauty of a green wall that is the focus.  Indoors, the wall provides a reprieve of sorts from unfavorable seasonal elements.  Yet there is more to it than that.  Studies have proven the effectiveness of potted plants to remove harmful VOC’s from our dwellings and workplaces.  Green walls would provide an opportunity to add an increased vertical canopy of “Green Vegetation” per square foot in comparison to potted plants on the horizontal plane of the floor.  With sky high retail leasing costs, monetarily speaking the green wall is shown to be the economic choice with added benefits to increase marketing potential, employee productivity, preventing absenteeism and simply provide an un-measurable benefit we call the “Wow Factor.”

Next time you’re indoors and you're feeling tired, have a head ache or dry itchy skin, think about what adding soothing, living, breathing plants to a space can do for you, the people around you, and the environment.

George Irwin, The Green Wall Editor

2. Ibid.
3. Ibid.
5. Wood, R, Orwell, R, Tarran, J, Burchett, M, 2001, Pot-plants really do clean indoor air, Nursery Papers, NGIA 

Successful Maintenance on Green Walls
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin, unless noted
October 7, 2008

For many of us the summer is almost gone except for the occasional spike in temperature - the last long rays of sun and the ever changing colors of explosive reds, oranges and yellow leaves are upon us.  For others the change of season is a minimally noticed drop in temperature and a little less sunshine; for others it’s the rainy season.  No matter where you live, some type of change is inevitable.

As our green walls change how do we maintain them and ensure their success?  As you may know, "Green Wall" is used as a global term for both living walls and green facades, for definitions refer to “An Intro to Green Walls and Green Roofs: Living Architecture at its Best - Green Walls Part I Nomenclature.”  We will talk about maintenance variables that will affect the changes and the “How To” application of maintaining green walls.


Variables of Maintenance.

A long overdue topic, I apologize for the limited writing schedule and to talk about exterior maintenance may be a few weeks late for those in the regions experiencing extreme changes from summer to fall, but nonetheless maintenance can be defined by using many variables.  The five topics to maintaining a green wall we can clearly identify as: location access, structural inspections, irrigation, and drainage and plant maintenance.  For a formal maintenance plan, our commercial maintenance technicians utilize our standard task of events or a simple checklist for all five variables on a monthly basis.  We refer to the checklist as a preventative maintenance program.

Before we dive right into the maintenance, a reminder that the non-vegetated components, whether part of a soil based modular system for a living wall or a cable / modular trellis system for a green facade, are mechanisms to hold plants in place and to offer the basic needs for plant survival.  Rethink a simple potted plant. (I have referenced this point in other writings.)  The pot, no matter how large or small, clay, plastic or metal, is a holding mechanism for the plant.  Traditionally, the pot is filled with a growing media that can support a root structure, hold nutrients and when placed in the correct amount of light and provided with enough CO 2 will usually survive.

If the pot contains a plant that needs sun and you keep it in the shade and it does not survive, do you blame the pot?  The point is to choose a plant type that is relevant to the sun aspect and microclimate of the green wall structure and therefore conducive to the environment in which it will thrive.  Back to the case of the potted plant, can we really blame the pot if the plant fails or doesn’t perform?  Or should we rethink our choice of plant material relevant to the needs of the individual plant, its environment and the green wall mechanism?  The point is green walls are simply tools that allow us to host the living plants and help sustain vertical growth, so don’t always blame the system for plant failure: first evaluate the needs of the plants, plan your maintenance and plant characteristics for survival accordingly.  Although not all green wall products are created equal and some do a better job of maintaining plant health, most can be constructed of various materials such as metals or plastics and offer a variety of options including depths, which can all be taken into account by the designer.

That simple statement, “First evaluate the needs of the plant” will lead us to the components for the plants' survival…and ongoing maintenance.  The plant world can be difficult for the untrained botanist, so read the plant tags carefully prior to purchasing or stand by the advice of the green wall manufacturer.  Each plant species has a list of characters that depict what the ideal conditions should be.  Characteristics can be identified as what describes the plant.  It may include phrases such as, “A rapid growing ground cover that can turn red, bronze or brown in full sunlight.”  On the tag look for key words such as “sun” and “water,” “heat and drought tolerant,” “needs constant moisture,” “fast growing,” “potentially invasive,” and “hardiness zone.”  These are very important buzz words that describe the plant, what they need for survival and will define the maintenance needs!    We would have to write a lengthy book in order to decipher all the possible maintenance topics for individual plant types.


   Physical Advantages on a wall.


When it comes to plant material in a green wall, there are no secrets.  The same plant in the green wall has the same requirements as if it were planted in any horizontal plane.  The green wall, however, does provide some physical advantages.  The green wall provides an ergonomically advantageous position to working in the vertical plane.  This is especially true when an  edible crop wall is installed.

With crops, it is uncommon for the wall to be above six feet high so it is easy to work on by standing in an upright position,  unlike traditional vegetable gardening where you are always bending or kneeling.  The green wall panels can also be planted at a height comfortable for almost anyone making green wall panels ideal for healing gardens, assisted living activities, children and other physically disadvantaged scenarios.

Genie Lift to Access a Parking Garage.

We identified the five components to maintaining a green wall to include location, structural inspections, irrigation, drainage and plant maintenance.  Although maintenance is conducive to the plant type, the five headings are common threads to any of the green walls.

Location Access

Location in this sense is defined as the physical area the wall is located.  For example, is the wall behind a secondary structure, is the wall only on an upper location of a building or is the wall fifty feet off the ground?  No matter what the plant type, the first item of consideration is how to access the green wall.  Usually a similar method used during the installation would be ideal.  If the installer used a scissors lift or a man lift the same equipment would be acceptable for major maintenance such as plant replacement and major pruning.  For general service and site visits a ladder may suffice.

Structural Inspections

It is recommended that any of the green walls be approached from a preventative methodology.  The fact of knowing the potential issues that may occur allows planning maintenance around these issues, creating a simple task analysis and level of hierarchal importance.  Even the most experienced installers are not exempt from mechanical failure so check your waterproofing and penetration methods.  In addition, if you are a customer or client of a green wall manufacturer/installer, question these methods and ask for specific details - remember that water will find the smallest penetration.  The structural bracket assembly on some systems is very complex and warrants an in depth inspection, while others are designed with simple functionality allowing for simple physical performance and free water and air flow behind the green wall.

Left: Ladder used for an indoor installation; Right: Scissors Lift.



Green LivingTM Wall
Bracket Installation


Upon accessing the wall the first order is to visually inspect the structural integrity of the mounting mechanism, the waterproofing, if any, and the interior wall (for any signs of moisture).  For trellis and cable systems check the penetrations of the anchors, spacers, and supplementary equipment in addition to the cable tension.


The second order of events is to operate and visually inspect the irrigation system.  Some items to look for include: clogged emitters, leaks at the coupler and connections and small drips within the irrigation manifold.  At this time it is ideal to remove and clean or replace the filter or screen from the drip irrigation system.  This will prevent any sediment from entering the thin tubing of the drip line creating clogs and emitter malfunctions. The irrigation is easier to assess with a trellis or cable system assuming the plant and the root system is at the base of the mechanism used to support the climbing plant.  The irrigation, no matter a bubbler, soaker, drip or other low volume technique, should be working to the original specification.  It is also a good idea to check the mechanical components such as the timer, zone valves, screens and any connections.

Left: Greenscreen; Right: Stainless Steel Anchor



     A ccessing the irrigation for inspection.


           Drip Irrigation Filter


Drainage Maintenance

During the irrigation inspection is also the opportunity to check all the connected drains that collect the excess irrigation and rainfall.  No matter the location, interior or exterior, a drain is essential to prevent water collection in the event of a heavy rain or an irrigation failure.  If the irrigation is left on or becomes the victim of a faulty irrigation zone valve, there is the possibility of the water overflow.  The drain acts as an overflow thus inspection of the intake must be part of the inspection process.  Materials such as dead leaves, soil, mud and even public garbage have been removed from the irrigation drains!

Plant Maintenance

The last order of inspection includes the actual plant material.  As mentioned earlier each plant has its own maintenance requirements.  A common maintenance requirement for exterior green walls is to weed the wall.  In this step, the trellis and cable systems are more susceptible to weed growth since the area the climbers are planted is on the horizontal surface.  Unlike the soil based green walls, weed seeds have a harder time rooting on a vertical plane.  Nonetheless, weeding is a common practice in all system types.

Other common practice includes the physical inspection of all the plant material.  The visual health would be obvious - disease, dieback, dead foliage and the noticeable and acceptable levels of overgrown plants.  It is common that some of the indoor plants suffer yellowing leaves that can be easily pinched or some climbers may become woody and can this can be solved by pruning.  It is at this time that the plants can be pruned, trained and cleaned.

Interior plants may require a dusting to keep them healthy.  After wiping any dust from indoor plants, you can also apply a thin coat of a non-toxic plant shine to bring out the plant colors and textures.  This is also the time to inspect for any erosion or media loss and the look of the non-vegetated component of the product itself.  Look for cracking, and in some green walls there is a growth media bag that may require replacing.  On the exterior, the metal-based products are not susceptible to expansion and contraction nor suffer from the heat and cold of the elements and exposure to the sun.    Also during the plant maintenance checkpoint, inspection of the structural integrity of the wall mechanism may be easier.  This is an opportunity to see the internal portions of the green wall that are usually covered by foliage!

Left: Fungus development due to improper watering; Right: Leaf Shine product

Finally, as a miscellaneous item, if the green wall system has artificial lighting this is a good time to check the bulbs for replacement.  With a planned preventative maintenance program the physical structure and integrity should be inspected on a monthly basis.  Irrigation operational failures will be more obvious since the plants will be on the decline, and leaks could become a costly event.

Supplemental Indoor Lighting is like jewelry, accessorizing and highlighting the green wall's best feature - the plants!.

No matter if you are a do-it-yourself green wall owner or a professional maintenance technician and installer, preventative maintenance will retain the safety and integrity of any project, plus add years of sustainable beauty to any wallscape.

George A. Irwin, The Green Wall Editor

How Does Your Garden Grow?......Vertical!
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin unless otherwise noted
July, 2008

Green peppers on the vine.

The early Spring is normally our busy show season and between the Go Green Expo NYC and GRSC in Baltimore, it is great to be back home.  Beside the busy spring show season it is also time to garden! Personally, my gardens have become my time to relax, and even better an opportunity to involve my family.  The kids help plant and my wife makes jam and pickles from what we harvest.

Since 3,000 BC families produced crops for their own consumption and some marginal barter.  In 1840, 69% of the labor force was farming, in 1930 it was 21% and in 1990 only 2.6% of the labor force is farming (  There has been an obvious decline in farming in North America since the 1800’s.  Before we talk about green walls I want to review some key points in history about American agriculture.

Planting a Victory Garden for the cause was patriotic and sustainable.

From 1939 to 1945 the world was at war, and Americans were asked to divert materials and efforts to the war effort.  At the time this was a call for self-reliance, recycling, and conservation of raw materials.  Sounds like another definition of Sustainability … Compare the circa 2008 vs. the 1940 definition of self-reliance, amazing how history repeats itself.  The public was encouraged to plant “Victory Gardens” in all shapes and sizes.  “Nearly 20 million Americans answered the call.  They planted gardens in backyards, empty lots and even city rooftops,” (

A small spot will do.

According to the U.S. Department of Agriculture an estimated 20 million victory gardens were planted.  Fruit and vegetables harvested in these home and community plots were estimated to weigh 9-10 million tons, an amount equal to all commercial production of fresh produce.  The program made a difference except after the war, the promotion of gardens stopped and the commercial agriculture industry was not prepared for the demand, creating a shortage of fruits and vegetables.  During these times of urban gardens there was also a significant decrease in transportation going to and from the market.

As I write it makes me realize that either my wife or I are at the grocery store at least 4-5 times a week for bread, milk or some type of produce.  What if we would simply grow all of our own produce and eliminate 3 trips to the store?  As the farming labor force decreased and the urban farms changed so did agricultural technology, including the introduction to pesticides, machinery, seed altering genetics and growing methods.

Homemade pickles and strawberries for jam grown at home in the Green Living™ Wall.

Let’s go back to basics; you don’t need a plot of land to maintain your own crop-producing gardens.  With evolution and urban development, the removal of fertile land was replaced with concrete and buildings and there arose alternative ways to produce crops - you guessed it, green walls for crop production.  As per my last article it’s not all about the “Outer Beauty…’s also the Inner Function.”

My wife is a traditionalist and we prefer not to purchase pickles, jams and jellies; we do our own canning when possible. In fact, we grow our own strawberries for strawberry jam, harvest our own salad and spinach and even grow thumbnail carrots, squash, cucumbers and more.

Re-visit “Green Wall” (Green Walls Part I) as a global term used to reference a variety of vegetated wall surfaces.  Within the term “Green Wall” we have two specific categories, Green Facades and Living Walls.

‘Green Facade’ or facade greening features a training structure that support vines or climbing plants growing upward from the ground away from the building (GW101, 2008).

Green Facade can now be dissected into two additional categories of product applications:
• A multidimensional, welded wire trellising system;
• A variety of stainless steel cable and mesh systems.

Both systems support a variety of climbing plant material, can be customized, and some are available in a variety of colors.

‘Living Wall’ is part of a building envelope system, comprising pre-vegetated or planted on site panels containing plants, growing medium or liquid nutrient installed in or on a frame, secured to a structural wall, or it can be free standing (GW101, 2008).

Living Walls can also be migrated into two distinct categories:
• Hydroponics wall which uses recirculation water to deliver nutrients directly to the roots of the plant material;
• Soil or growing media based walls. T hese walls are made up of a variety of modules that retain growth media to support plant material.

You want to have a vertical garden, what system do you use?  The question is for you to question or talk with one of the manufacturers mentioned.  When I lecture about green walls I make it clear each system has their limitation; each has pros and cons.  Many features include plastic vs. recycled metals, powder coating, growing media depths, drainage, watering systems, mounting, maintenance and more.  The common point is that when vegetation survivability issues arise, the system itself is not to blame for plant failure.

Look at the system just as you would a terracotta pot.  If you plant the correct plant in relation to the pot, allow for proper lighting, nutrients and care for your plant, it will thrive.  If the basic needs of the plant are not met or the plant is not right for the pot and the plant dies, do you blame the pot?  The same hold true to the green wall systems.  You need to choose plants that are conducive to the environment and care you apply in relationship to the systems limitations.

The cable and wire mesh systems (Greenscreen, Jakob, CarlStahl) would be more then adequate for climbing grapes, beans and supporting tomatoes, but require an area below to support the root structure.  Without a planter or space requirements these systems are limited for vertical crop production, unless the plant is a climber.  Some of the living wall systems have more limitations then others.

The standard ELT living wall panel has a 2.25” depth and would be best suited for fast growing leafy greens and some shallow rooted herbs that can be harvested during the early season.  The Green Living™ Wall by Green Living™ Technologies offers a wide range of planting depths from 3” to 6” and has shown long term success with everything from tomatoes, cucumbers, zucchini, carrots, eggplant, strawberries, peppers and even watermelon.  Both systems can produce edible foods with the use of growing media supported on a vertical surface or free standing.

Left:  ELT Living Wall Panel; Right: Green Living™ Technologies

Making a choice of systems for your garden may be dictated by the area you have to work with, and most of the systems are very flexible from a design perspective.  Greenscreen will customize the project to specification; Jakob and CarlStahl are very flexible since they are cable systems and can be assembled with average carpentry skills to meet any dimension.  The ELT system consists of a single plastic 20”x 20” panel that can be cut horizontally.  Measure carefully because cutting the structure vertically will remove one of the side walls and irrigation will flow outside the structure, so try to keep your measurements of the ELT panel even in order to prevent cutting them vertically.  The Green Living™ Wall has very flexible dimensions and has standard stock in 1 foot increments and they can customize any other measurement or curve you request including planting depths from 3”, 4” and 6”.

Left:  ELT Living Wall Panel with Leafy Greens; Right: Strawberries for jam in the Green Living™ Technologies standard 4” depth.

Other options for growing vertical or at least elevated crops can be demonstrated here using an old cat litter container with a hole drilled in the bottom and painted green.  The owner also planted Basil in the top.  Special thanks to for sharing.

A kitty litter bucket-turned vegetable planter!  Source:

Here are some examples of some of year's Irwin family's crops including watermelon in the lower left hand side of the picture on the left.  In the past we found that the following can also hold themselves on the wall without any problems or soil loss: tomatoes, peppers, leafy greens, strawberries, herbs, thumbnail carrots, and dandelion.

Irwin Family hanging vegetable crops.

In addition to the above examples, the following is showing a 100% success rate with the help of a rack system under the panels to support the fruits which include: watermelon, zucchini, cucumbers and squash.

Left: Cucumbers at 9 weeks; Right: Tomatoes on the vine with GLT.

Wheat grass is a snap on a wall.

How about growing your own wheat grass?  In my travels I found energy shots of wheat grass selling for as high as $9.00 per shot.  The truth is, you can grow your own for pennies. The picture at left is a juice bar that has panels of wheat grass growing out back while the one below is in the store is cut for use in a variety of energy drinks and smoothies.

If you grow it, you know it!

How does your garden grow?  I hope you enjoyed these gardening ideas, agriculture history and the rejuvenation of what I like to call the “Sustainable Garden” instead of the Victory Garden.

 Remember that each system has various limitations, space consumption, potential mounting possibilities, and applications as some units can be indoors.  Even the material it is manufactured from can play a role in a successful vertical garden.  It's not rocket science if we can grow our own produce, especially during the geographic growing seasons, and if we could we eliminate trips to grocery store, what would the residual results be?  How much in gas could we save?  How much carbon can we offset?  And the issue of food security would rest with us at home.

Go out and garden - the worst thing that can happen is you end up with great organically grown tomatoes and you spend time with your family doing it.

George A. Irwin, The Green Wall Editor

Green Walls: Outer Beauty, Inner Function
By George Irwin, The Green Wall Editor
All Photos Courtesy George Irwin unless otherwise noted
April, 2008

As a child I was mesmerized by the bean seeds starting to poke up over the rim of old cafeteria milk carton that had the top cut off.  I clearly remember my teacher lining up the milk cartons, mostly chocolate, along the window sill.  As the week went on the mass of bean seeds look like a single carpet - I thought that was neat.  And as a teenager I always admired the clean cut and straight lines of a professionally manicured lawn.  Seeing the dark and light striped green color variations of the outfield grass I would ask myself how they did that - and I thought that was cool.  As a young landscape entrepreneur the site of mass annual plantings, over grown trellises and displays of natural wild flowers would make me stop and look, and that too, was pretty awesome.  These are all very specific things that caught my attention.

Touchy, feely and gorgeous in Rochester, NY using Green Living Technologies, LLC;
Design by Pietro Furgiuele.

These visual experiences are all related to color, shape, texture and presentation; the point is it was eye catching.  You don’t need to be a psychologist to realize that visual affects are an attractant and at times stimulating.  Of course there is more to just visual attractants than plants; in fact, anything can be a visual attractant depending on what it is and who it is perceived by - but green walls are different, and I haven’t met anyone yet who didn’t think a green wall wasn’t “cool.”

Here we will discuss the use of green walls as visual attractants, artistic expressions, marketing campaigns and one of a kind pieces of art.   Although most will find the green wall itself a work of art, you have to look beyond the initial beauty to see that there is also environmental and economic function.

In my last article, “An Intro to Green Walls and Green Roofs: Living Architecture at its Best,” we left off with the understanding that seeing plant material on a vertical surface stimulates curiosity and verbal excitement with words like: Cool, Wow, Neat, Different, and sometimes even words of disbelief: “Is that real?”  It is these same people that are bringing the green wall to the attention of others with expressions like, “Look at that, Isn’t that neat, and Check this out;” they express a call to action that recruits others to share the visual experience with them.  The Austrian designer Friedenreich Hundertwasser could be considered the modern artist and visionary who promoted the concept of living vertical architecture, and even to this day visitors are amazed at his integration of vegetation and architecture on green wall and greenroofs.  See some of his work green wall below:

Hundertwasser-Haus, Vienna, Austria: 1977-1986; Photo Copyright Glenn Bristol;

RIT Green Living Wall™

A recent example came from a project at a much respected college, Rochester Institute of Technology (RIT).  A small monolithic 100 square foot Green Living™ Wall system, nothing of vibrant color, was being installed in a brand new LEED™ certified building there.  If the installer hadn’t tied off caution tape, students and faculty alike would have walked right up to where the installer was working to touch the wall.  In addition, those same passers by came back with more people to show them, and the audience soon multiplied.

Right now, 100% of our calls about green walls come as a desire for a cosmetic addition to an indoor space or outdoor facade.  But, it is also becoming more prevalent from our other business partners and corporate clients that incorporating a green wall can also be a stoke of marketing genius.  My inaugural article also described in brief about the Anthropologies green wall in Huntsville, Alabama.  One of the unanticipated benefits about that green wall is that it attracted people resulting in an increase of retail traffic.  Since then, we are not the only ones who have realized the marketing potential; we have been working on three additional green wall projects for the same company, and they, too, realized the impact.

Lexus and Pangea Organics' “Nurture Nature” event specialty GLT display.

Earlier this year we were contracted by Lexus and Pangea Organics for the NYC kick off event “Nurture Nature” wanting to rent a full 10’x10’ custom green wall and logo as a backdrop for the guest speakers!  Using a combination of indoor plants and wheat grass grown in between the Pangea logo, the backdrop maintained the attention of all the guests long after each speaker was done, and of course they walked right up to it and touched it in disbelief.  The green wall gave the guests something to remember and in addition they will more than likely remember the sponsors commitment to being green.  To infuse the attendee's memory even deeper with the message of cool green, a single cell Green Living™ Desk Top (a mini green wall specifically designed to accommodate a single plant) had been created with the sponsor's name and logo and given away as a parting gift.

Lexus and Pangea Organics' “Nurture Nature” organic, living parting gifts.

Pure Yoga in New York City; GLT rendition.

Pure Yoga, an Asian based company, has expanded into NYC with its first international location and is making a public statement by using the Green Living™ Wall system as its facade.  Opening in June of 2008, the 1,000 square foot Green Living™ Wall was designed by plant artists, creating a mural of vegetation.  Currently there are multiple blue chip corporations working on a green wall realizing it is a visual attractant.  These are small but influential marketing examples of companies who are seeing the visual impacts of implementing green walls.

The aforementioned are green walls of marketing substance, so how does one embrace the green wall as part of their own lives?  Let’s take it one step deeper, the "Green Walls as Art" term coined by Green Living™ Technologies, creates or better yet incorporates limited edition, one of kind pieces or the adaptation of the vegetation to complete an application that is outside the standard.  The Green Wall as Art is not a square mural on a building facade.  Rather, plant material combined with geometric shapes, a variety of material finishes, sizes, colors and even the perception of the green wall itself makes up the artistic venue.

MFO Park in Zurich, Switzerland

In fact, the inspiration of Green Walls as Art came as a combination of plants and the structural element inspired by the MFO Park in Zurich, Switzerland.  The custom cable system allowed the plant material to resemble starbursts, intriguing and ironic that the park is used as a platform of multi media and artistic events such as a place to gather socially, concerts and art festivals -  unbeknown that the park itself is art.  This urban park raises form the ground as the vegetation reaches for the sky.

The work of Green Living™ Technologies sculptress Susan Rowley (Rochester, NY) has also included the aesthetics of green wall technology and custom sculptures.  Pictured above is a limited edition green wall hand crafted from stainless steel.  Each piece has a one of a kind finish since each one is done by hand.  Also pictured is the work of Greenscreen’s columns and 3D curves.  Combining geometrics and architectural design to the green wall will always provide visual impact.

Technology meets art: Left: NY sculptress Susan Rowley combining sleek stainless steel with soft plant material; Right: Look at this shape - imagine the possibilities! Source: Greenscreen

A leading designer of stunning visual green wall mural art is Patrick Blanc, who hails from France, and author of the soon to be released The Vertical Garden: From Nature to the City.  His "vertical gardens" are renown for their scale, innovation and great variety of plant material, and he is the creator of Le Mur Végétal, a copyrighted system:

Musée du quai Branly vegetated "Vertical Garden" wall by Patrick Blanc in Paris, France;

Can we agree that the green wall is a form of art that attracts people to it like the sound of a waterfall?  So then is the green wall the silent waterfall?  Green walls are more then beauty, the added bonus is they are also functional.  Go figure that they do more than look good, who would have known!  Enough sarcasm, let's get serious for a second: did you know according to the American Farmland Trust the usable farmland in the U.S. is shrinking by 2.2 million acres per year (  The changes in land use to our urban society have caused huge increases of runoff and flooding.  The same changes are causing habitat destruction for flora and fauna and, of course, there are the common results of increased urban heat island effect, noise pollution, poor air quality, etc.  This is not an excerpt to explain the effects of over-development but to stimulate thinking how green walls are also functional.

Let’s assume our society stops the clock on development.  Using farmland, for example, we may not have enough to sustain the growing population, but be sure there are plenty of new developments with zero-land lots with plenty of vertical space.  Who is to say we couldn’t utilize the green wall as crop production?  Yes, we have seen grapes on trellises, but really how about growing peppers or tomatoes?  Vertical growth is already happening across the globe on roofs in many cities like Toronto, New York, and Singapore, for example.

Changi General Hospital in Singapore. The Hydroponic microfarm on its atrium roof since 1988 feeds patients;

Green Living™ Technologies, Strawberry Establishment for Green Wall

And from our end, Green Living™ Walls are being manufactured in 4” (11cm) to 6” (15.25cm) depths to accommodate a variety of deeper rooted plant material and editable crops.  The first commercialized walls (4) will be installed this summer (2008) in the Los Angeles California region in collaboration with and Cal Poly Tech to produce editable crops for homeless people.  Green Living Technologies has partnered with Cal Poly to conduct further research to consist of storm water collection, heat absorption and acoustic values.  The edible walls will contain a variety of crops that can be eaten raw to include: beans, tomatoes, peppers, leafy greens and strawberries.  The lower cells of the wall will contain larger crops such as cucumbers, melons and eggplant supported by the ground itself while the roots thrive in the media within the green wall.  In R&D look for dwarf blueberries and no-bog cranberries and let’s not forget vertical herb gardens!

Many butterfly feeding and breeding habitats have been destroyed by pesticides and urban development (  Butterflies are easy to attract; you just have to know what they like to eat.  Caterpillars eat "larval" plants like milkweed, marigolds, Queen Anne’s lace, and violets.  Butterflies like "nectar" plants, like the butterfly bush, the beauty bush, sunflowers, lilacs, snapdragons, and zinnias.  So select plants that are diverse in color and bloom at different times, and you will attract butterflies all summer long.  Using butterflies as an example, green walls can be planted to refurbish and repopulate natural areas that have been destroyed quite effortlessly.

Green Living™ Technologies

Poor indoor air quality (IAQ), also known as “Sick Building Syndrome,” can be many times worse than the air outside (  Pollutants can cause or contribute to short and long-term health problems, including asthma, respiratory tract infections, allergic reactions, headaches, congestion, eye and skin irritations, coughing, sneezing, fatigue, dizziness and nausea.  Some facts:

• Indoor air pollutants can cause discomfort, and reduce attendance and productivity.  Recent data suggest that poor IAQ can reduce a person's ability to perform specific mental tasks requiring concentration, calculation, or memory.
• Indoor air pollutants hasten building deterioration.  For example, uncontrolled moisture can result in mold growth that leads to the structural decay of building components.
• Poor indoor air quality strains relationships among employees, family members, parents, teachers, students and school administrations.
• Indoor air quality problems can result in liability issues or lawsuits.

Green Living™ Technologies

According to NASA, the use of indoor plants has proven to remove such chemicals as Benzene, Formaldehyde and Trichloroethylene.  My experience  with this is that we have an indoor growing facility in the same area of manufacturing and although we haven’t done a formal study, it is true that the area with the plants is a much more comfortable area, supporting the psychological benefits argument to having indoor plants.  Indoor plants are also supported by the U.S. Green Building Council.  Numerous studies including those done by over 10 prominent researchers worldwide demonstrate that the ability of plants to metabolize Volatile Organic Compounds (VOCs) increases with extended exposure to VOCs.

The health effects of exposure to VOCs are consistent with Sick Building Syndrome effects, including eye/nose/skin irritation, headache, and lethargy.  Several studies have also shown lower workplace stress, a decrease in fatigue and enhanced productivity by adding indoor plants to their interior environment.  Two points are available in LEED - Office Interiors Indoor Environment Quality Credit IEQ-15 'Indoor Plants' to encourage and recognize the installation of indoor plants that improves indoor environment quality.

Green walls also improve exterior air quality.  Air quality is directly linked to the urban heat island effect.  Adding green walls results in a reduction in urban temperatures through the reintroduction of plants that would positively affect air quality by the reduction of smog days and air born particulates.

Green Living™ Tabletop w/ Basil

Remember that kid in the beginning of the article who was impressed by the bean plants?  He is all grown up now with his own kids and refuses to let another bean plant die.  Seriously, green walls can be introduced to the classroom.  Instead of growing that little bean in a washed out milk carton we can now open up the minds of students from 1st grade to higher educational studies with opportunities to introduce data and newer technologies.

Without assuming, there may have been a notion of the same song and dance about the obvious benefits of green walls in comparison to green roofs such as the prevention of storm water runoff, curbing the heat island effect, monetary savings and doubling the life expectancy of the roof membrane, etc.  And all are valid and key points.  This article was to get you to think outside the box - who would have thought to use green walls as a major contributor of crop production and to replenish butterfly habitat?  Well, we're not quite done, either.  How about job creation?  Green walls in all their beauty and function create green jobs through manufacturing, training, installation and maintenance contracts and so yes, the obvious theory in comparison to green roofs becomes more apparent.

Musée du quai Branly by Patrick Blanc in Paris, France;

Thanks for reading and it was my intention to get you to think about the many possibilities for green wall applications, how they are used and what some of the benefits are that we can implement now.  For now, green walls provide a visual impact that cannot be denied and our feedback from clients say that since there are plants it must be “green,” when in fact the beauty is only as deep as the wall itself - what you don’t see is just as important.

George A. Irwin, The Green Wall Editor

March 2008

guest feature and inaugural column for The Green Wall Editor

An Intro to Green Walls and Green Roofs:
Living Architecture at its Best

By George Irwin, Industry CEO and President
All Photos Courtesy George Irwin unless otherwise noted.

Photo Source: Carl Stahl DecorCable Innovations Anthropologies, Photo Courtesy George Irwin

Left: Lincoln Park Zoo in Chicago, IL, Source: Carl Stahl DecorCable Innovations;
Right: Anthropologies in Huntsville, AL, Source:
Green Living™ Technologies

Green Walls Part I: Nomenclature

Since the days of Babylon, vegetation has been growing on, in or around both the horizontal and vertical planes of buildings, more specifically the roofs and walls.  The most recent green trends have been including a variety of what the industry is calling “Green Walls, Living Walls, and Vegetated Façades,” and we have heard many more names, too.   The green roof movement has naturally evolved to green walls - no pun intended, but the green roof has now climbed over the parapet and down, or up the walls.

Designers, architects and engineers now have the possibility of encasing a building in some type of live vegetation whether for aesthetics, function or notoriety.  This article is the first in a multi part introduction to “Green Walls” that will define the nomenclature contributed by the leaders of green wall manufacturers, installers, designers and architects with support from Green Roofs for Healthy Cities (GRHC) and Green Walls 101© (GW 101).

Green roofs have multiple design and material components and so do green walls.  Each project must be addressed with a variety of application possibilities, limitations, functionality and aesthetics.  In order to understand the potential components relevant to specific applications we have to define the terminology of “Green Walls.”

The term “Green Wall” is a global term used to reference a variety of vegetated wall surfaces.  Within the term “Green Wall” we have two specific categories: Green Façades and Living Walls.

‘Green Facade’ or facade greening, features a training structure that supports vines or climbing plants growing upward from the ground away from the building (GW101, 2008).  Green Facades can now be dissected into two additional categories of product applications:

• A multidimensional, welded wire trellising system.
• A variety of stainless steel cable and mesh systems.

Both systems support a variety of climbing plant material, can be customized and some are available in a variety of colors.

Photo and System: Greenscreen Photo and System: Jakob

‘Green Facades’
Left: Welded Wire Trellising System,
Source: Greenscreen; Right: Cable and Mesh System, Source: Jakob

‘Living Wall’ is part of a building envelope system, comprising pre-vegetated or planted on-site panels containing plants, growing medium or liquid nutrient installed in or on a frame, secured to a structural wall or it can be free standing (GW101, 2008).

Living Walls can also be migrated into two distinct categories:

• Hydroponics wall which uses recirculation water to deliver nutrients directly to the roots of the plant material.
• Soil or growing media based walls.  These walls are made up of a variety of modules that retain growth media to support plant material.

‘Growing Media Based Living Walls’
Left: 5th Avenue Green Wall in New York City, NY, Source:
Green Living™ Technologies;
Right: Aquaquest, the Marilyn Blusson Learning Centre, Vancouver Aquarium in Canada,
Source: Randy Sharp,
Sharp & Diamond Landscape Architecture

Recognizing the correct terminology is the start to deciding on a green wall system.  Be warned not all systems are the same there are pros and cons to each system.  Not all are “Do it yourself” applications, some perform only with a specific plant type or have a variety of mounting procedures and structural requirements...and more.  For more information contact the manufacturer.

Green Walls Part II: The New Green Roof?

In case you don’t read the newspaper, watch the news, have internet access or any other media attention whatsoever, green roofs have proven themselves over and over again long term to be part of a Best Management Practice (BMP) in the fight of global warming.  Long term data has proven that Green Roofs, when constructed correctly can:

• Retain and / or slow down a significant amount of stormwater runoff resulting in less erosion, reduced heavy metals in our water ways...etc…
• Double the life expectancy of a roof membrane
• Add acoustical value
• Regulate a building's internal temp
• Clean the air

And etcetera, etcetera, etcetera…

The marketplace by Oviedo Crossing by Greenscreen

The Marketplace at Oviedo Crossing, Oviedo, FL; System: Greenscreen

There is one problem with the green roof and all its beauty and function...Unless it is yours and you have access to it, no one else can see the green roof (unless you are in an adjacent building).

Green Walls, on the other hand, can be a public display of beauty, art, expression and just as important as green roofs...functional.  Green roofs have long term quantifiable data associated with them.  Without boring you with statistical details, it can be theorized that a green wall will provide similar or associated benefits.  Here is where the benefits may vary, depending upon the array of systems available; trellis systems, cable systems, growth media based systems, or a hydroponic system.  With multiple systems come multiple benefits that may or may not carry from one to another.

A true correlation of green roof related benefits must be under a similar design.  For example, the use of a 3” growing media based system should have a benefit correlation to a 3” depth green roof with similar vegetation properties.  These same benefits cannot be expected with a trellis or cable system.  However, the facades (trellis and cable system) can offer a multitude of other benefits not offered by a soil based system.  This is part of the pros and cons mentioned in Part I.  As a designer or architect it is up to you to decide on the system and its functionality. (Note: As a designer why not incorporate a multitude of systems in one project?)

The connection to the benefits will rely on the system, we can agree on that.  Specifically speaking, what benefits do all the systems share?  Cosmetics and aesthetics...fact is, when constructed correctly the green wall applications are very alluring and appealing.  What do aesthetics do for me?  As a non environmental benefit we used the example of the 2,000 square foot Green Living™ Wall for Anthropologies, a high end retail store in Alabama, and it attracted additional pedestrian traffic immediately to the store front - it can only be assumed that the increase in traffic equates to a rise in internal traffic / shoppers, increasing revenues for the retailer as a result of the extra attention, capturing those sales based on an interest in the green wall.

Anthropologies by Green Living Technologies Green Living Technologies

Left: Anthropologies; Right Green Wall Detail; Source: Green Living™ Technologies

No matter what the system or plant material, there is a definite attraction to seeing a potpourri of plants cascading from the vertical heights of what would otherwise be an orthogonal boxlike structure.  Some of the manufacturers have the ability to custom manufacture specific dimensions, create curvatures, and are now are incorporating green walls as art both indoors and out - green walls and green roofs as living architecture!

MFO Park National Wildlife Federation

Left: MFO Park in Zurich, Switzerland; Right: National Wildlife Federation Headquarters in Reston, VA

Whether you are an interior decorator, architect, landscape architect or just simply interested, visit for more information on attending "Green Walls 101 Introduction to Systems and Design" in a city near you.  You can also visit Green Living™ Technologies in NYC on April 26-27, 2008 at the Go Green NY Expo and on April 29 – May 3rd in Baltimore, MD, at the 2008 Sixth Annual Greening Rooftops for Sustainable Communities Conference.

Be sure to visit again for additional Green Wall articles!

George A. Irwin, The Green Wall Editor



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