Greenroofs.com: The Green Walls Column

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

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 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.

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.

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 (www.urbanfarming.org).

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.”

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!”

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.

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.

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.

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.

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.

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.

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 info@agreenroof.com.

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: GreenWallEditor@greenroofs.com, George@AGreenroof.com, www.agreenroof.com, or 1.800.631.8001.

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.

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.

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 Greenroofs.com 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.

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.

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.

"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.

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.

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

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.

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

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.

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

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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 ₂will 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.

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.

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 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.

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.

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.


A ccessing the irrigation for inspection.

Drip Irrigation Filter

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!

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!

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.

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

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 (www.agclassroom.org/gan/timeline/index.htm). 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.

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,” (http://www.livinghistoryfarm.org).

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.

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…..it’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.

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 www.marshalllee.net for sharing.

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.

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.

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.

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.

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:

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.

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.

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.

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; Courtesy Greenroofs.com

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 (http://www.wvfarmlandprotection.org)? 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; Courtesy: Greenroofs.com

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 www.urbanfarming.org 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 (http://www.projectwildlife.org). 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.

Poor indoor air quality (IAQ), also known as “Sick Building Syndrome,” can be many times worse than the air outside (www.epi.state.nc.us/epi/air). 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.

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.

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.

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.

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.


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

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.


‘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…

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.

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!


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 www.greenroofs.org 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 Greenroofs.com again for additional Green Wall articles!

George A. Irwin, The Green Wall Editor