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Technology, Liabilities,
and Growing Media: Change is Good
By George Irwin, The Green
Wall Editor
Photos Courtesy George Irwin Unless Otherwise Noted
April 21, 2010
The Green Walls Column
Unlike
the usual spring article when I'm usually complaining about being
busy with tradeshows and with preparation for projects or travel,
here it is April and I did not get my first article ready by February
as anticipated. I’m much disciplined when it comes to getting things
done on time, so I'll blame it on others around me for being so
busy.
Our colleagues
and clients are just as busy. Why is everyone so busy? I’m blaming
technology. Before computers, PDA’s, cell phones, mobile Web and
laptops, it actually took days to send a letter - now a million
letters can
be sent in a single click, and the need for instant gratification
sometimes supersedes quality.
The rise
in technology has brought about change and, in most cases, change
is good. Products become better suited and applied, projects
become bigger and more intricate. The same is true for green
walls.
In January I had a chance to be a guest speaker at the
Tropical Plant Industry Exhibition (TPIE) in Fort Lauderdale,
Florida. One of the great things about being a speaker is
you have an opportunity to walk the tradeshow floor, meet others
who are doing research, propagate new ideas, form new relationships,
and see new developing products.
2010 seems
to be shaping up as what I see as the “Minimal Use Vertical Wall”
with a handful of new green wall companies. Nothing bad about having
a new company, we all started somewhere, however, not all green
walls are created equal. In fact, I have always talked about
the advantages of products developed for long term use. Let's
face it, there are some materials we don't want, or trust, hanging
on walls four stories high, but if you want to dress up your back
yard fence with a lightweight option (re-planting them year after
year), these minimal use green walls may be your answer. For example,
there are plastic bags and canvas pockets that hang from a wall,
another one that looks like a baby diaper pinned together, and the
ubiquitous upside down tomato growing sock.
Yet as
green walls become more popular, the projects become more intense,
the spectacles become more dramatic - and so can the liabilities.
As an industry spokesperson and a frequent visitor to industry shows
and events, two of many key questions I always seem to get asked
include the liability of installing green walls, and type of growing
media for green walls.
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Notice
that broken plastic is securing the product to the bracket.
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First let’s
talk about liability; here is where we may run into problems with
new, unproven companies entering the green wall market. Some
of the products offered are for all intents and purposes, bordering
on novelty or single season use (use it for one summer and throw
it away). For example, some of the products I have recently
seen or experimented with are advertising and displaying higher
mounting elevations than I would feel comfortable with installing.
There are
very few commercial grade green wall products with a proven track
record that are made to last indefinitely, constructed from materials
to meet wind and weight loads, accommodate extreme variances in
temperature and to withstand other regional abnormalities (e.g.
salt tolerance around coastal regions). Some of these new
green wall products, specifically some of the living walls, have
no track record at all.
Recently
I encountered a press release from a “New & Exciting” company introducing
green walls. After some in depth investigating and direct
knowledge, the company had no track record of manufacturing, installation,
training, certification, or a portfolio behind them.
Who is
qualified to install green walls? According to the
Chicago Tribune article "Turf wars, Chicago-style: Roofers vs.
green-roof landscapers" of October 2009, the
National Labor Relations Board (NLRB) favored the landscapers
over the roofers to be capable of installing green roofs at a lower
cost, and referring to roofers they pointed out that "they are no
less experienced but are more efficient at installing green roofs.”
Green roofs, fine, there is more than enough training opportunities
to learn about green roof installations; some companies provide
a professional certification course that credits them to be "Certified
Professional Installers" for that company's products, and other
opportunities are more generalized such as the Green Roof Professional
(GRP) accreditation offered by
Green Roofs for Healthy Cities.
Understandable,
and I accept the verdict by the NLRB hands down. I do, however,
have to speak openly about landscapers installing green walls.
Some of these projects, not all, involve a level of construction
not normally associated with traditional ground elevation landscape
work. I can freely comment because I was a landscape contractor
for 23 years before I, too, entered the green roof and wall arena
in 1999.
In comparison to traditional built in place green roofs, for the
most part a green roof tray system is relatively simple to install
- once on the roof it’s a simple matter of safely getting the trays
in position, and adding irrigation - which should be part of the
landscapers' knowhow. Overall, most roofers do not have the
background or knowledge set to diagnose and treat problems relating
to plant health, whereas the landscape contractor is ideal to be
the stand alone green roof installer and maintain the vegetation.
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Fig
1. Proper scaffolding is a serious job.
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Not to
say all green roofs are that simple, but for this purpose it’s just
not the same as green walls. There are no standards for green wall
technology, with multiple systems to choose from including green
façades and living walls (both growing media based and hydroponic).
Each system is different and each manufacturer should provide some
type of formal, recognized training for a safe installation and
the long term safety of an often large product hanging from a
wall.
Some construction
skills associated with the assembly of such systems require extreme
measures necessitating specific training; it’s not about simply
screwing brackets to a wall. For example, one of my company's
projects, the PNC Bank project in Pittsburgh, PA, left and below
(Figures 1 and 2), was prepared by
G-Space/ Philly Green Wall and Roof, a skilled, state licensed
design/build firm certified under our product's brand, and not installed
by landscapers. The vegetation was already mature and grown
into the system by a horticulturist and/or a growing facility, and
thus did not need the additional plant expertise of an experienced
landscape contractor. In this case it wasn't about the welfare
of the plants, but the physical installation including engineering,
crane operations, calculations, mounting hardware, job site preparation,
scaffold safety, fall restraints, etc.
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Fig
2. Prep Work to Accept a Living Wall.
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One
type of man lift.
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This is
not to say this is the norm for all green wall installations.
In my personal experience, even the largest of landscape firms we
have worked with globally do not have the knowhow, experience, and
insurance coverage to conduct a large scale green wall installation
over 20 feet high. Yet, it is here I have to cross over the
line and lean to the landscapers to rely upon for continuing maintenance
procedures. Pending the scope of work construction, contractors
are the large scale installation experts, and the landscapers and
growers are the plant experts who should, by all rights, also be
the maintenance personal.
This raises
the question about additional liabilities and working with extended
heights. May I remind you that the landscaper is not traditionally
adapted to working on scaffolds or in a man lift (a machine that
is like a boom that carries a person to an elevated height).
Green walls provide a new paradigm to the responsibility and job
description of the landscape contractor. This puts an even
bigger burden on the manufacturers to ensure they provide resources
for the maintenance technicians, requiring additional job safety
training and new equipment training. There is a place for both the
installing contractor and landscape contractor; having a company
who can provide a single service is ideal. Experience is a
foundation to lean on as a consumer, and “New & Exciting” could
potentially equate to “Dangerous & Liable.”
The second question that is always asked when I’m speaking or in
conversation is, “What about the growing media?” I always
respond, What about it? Fact is, for every company there is
more than likely a different method or medium they
grow in. I always use the word green wall loosely and remind
people that "green wall" is an all-encompassing term. And
growing "media" is the plural of growing "medium," so unless you
have more than one type of growing mix within a project, it should
be referred to as growing "medium." And when we're talking
about growing media, there are two areas to distinguish between
regarding placement in a green wall.
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Left:
Living Wall - Saul Nursery, Alpharetta, GA, Photo by
Caroline Menetre.
Right: Green façade - Desert Ridge Marketplace, Phoenix,
AZ by
Greenscreen;
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If we're
defining a green wall as a green façade, the growing medium would
be found at the base of a 3-D trellis type structure to support
climbing plant material and vines. In this case you should
have a growing medium that is rich in nutrients, drains well, and
has a pH level to support the type of plant material in its particular
location.
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The Musée du quay Branly
Hydroponic Living Wall by Patrick Blanc.
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If we're
defining a green wall as a living wall, that's a completely different
story since there are multiple locations to place the growing media
- or none at all. Follow up questions are necessary!
So when someone asks me about the growing media used in green walls,
first of all I have to politely ask if they're actually referring
to a "living wall." In confusion, the general public simply
assumes because it's vertical, it's a living wall. (You can
read an
archive of one of my earlier posts that clearly defines the
differences between a green façade and a living wall.) I've
found that more often than not, the question is clearly directed
towards a living wall.
To confuse
matters worse, the ever popular work of French botanist and designer
Patrick Blanc is defined as a true hydroponic living wall.
This means it does not contain any organic growing media; the plant
roots are fed with circulating water containing nutrients.
The definition of a living wall states that the roots are evident
throughout the entire wall, not just at the bottom as found in a
green façade. So, in this case, we have two types of living
walls - one with a growing medium and one without. Back to
the question, What kind of growing media is used in living walls?
Before I answer the question, you have to understand plants require
very few things, and aside from sunlight and the availability of
water, free drainage is key - the growing medium has to provide
the matrix to allow for water to flow freely in order to prevent
root rot, promote oxygen uptake and microbial action. Plants
also need to have the ability to extend their root system - if you
have ever purchased a plant where the roots are wound around the
inside of a pot, you know that plant is root bound and would have
eventually choked itself to death. A hard clay type of soil
would also restrict root development due to compaction and could
eventually kill a plant by drowning it.
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Sphagnum
Moss Wrapped in Wire Mesh.
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In addition
to preparing the medium for plant roots, consider the plant requirements
in relation to light, water and nutritional needs. Other than
the lighting, which allows for the plant to produce sugars for energy
and growth, everything about your plant should evolve around the
roots. Using the correct composition of growing medium will
strike a balance of air space, water and nutrients - if you have
healthy roots you will have a healthy plant, and if you have healthy
plants, you'll have a successful living wall.
Some of
the new designs starting to emerge consist of a variety of wire
meshes shaped into forms that contain a 3-D block of sphagnum moss,
coir husk or rock wool. Other bagged type systems use or have
used anything from peat moss to potting soil to any of the above.
The hanging pocket types, or what I referred to earlier as minimal
use, suggest employing “a high quality potting soil.” So with
three different types of systems, you may have three types of growing
media and methods to establish the wall. And not all growing
media are equal.
Currently, there are a variety of mechanical means to hold plants
on a wall, but I feel the greatest advances in green wall technology
are going to be in the growth media field. Rock wool, coco
husk, and sphagnum mosses are all very porous and popular in the
hydroponic arena.
Pros: They
allow for drainage, root growth and are lightweight. Cons:
They need a constant supply of irrigation and fertilizers, artificial
environment regulation (the need to always monitor the pH levels),
and there is no beneficial microbial activity, especially around
the roots of the plants.
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Top
View of a Coco Husk Insert.
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On the
other hand, quality potting soil mainly consists of peat moss; although
controversial and questioned as being a sustainable harvesting practice
since it involves older bog ecosystems, it provides the support
matrix needed to sustain plant growth. Media-based living
walls were introduced around 2004, and the growing media used was
a high quality potting mix. Personally, peat was the base
to one of our older medium recipes, with other added ingredients
and micro-organisms, which I can’t disclose because of trade secrets.
So I know firsthand that the type and quality of peat is of the
utmost importance. A newer bog provides a more fibrous peat,
which is ideal, allowing the final product to gather naturally to
form something like the commercially available pre-casted peat pots.
The fiber content in the higher quality media should be above 60%,
have a high water retention rate, drain freely, and provide a balanced
pH.
But the potting mix media also needed applications of periodic fertilizer.
To add additional controversy almost ignored and rarely published,
by comparison traditional lightweight extensive green roof media
hold minimal nutrients because of the lack of organic material -
and the result is the application of synthetic fertilizers to feed
the plants. Even though low maintenance, most succulents and traditional
sedum still need nitrogen (N), potassium (P), and phosphorous (K),
in addition to micro nutrients as part of a fertilizing plan.
When chemicals are not being absorbed, they become part of the runoff
in the traditional sense - the fertilizers are now making their
way to the waterproofing layers of green roofs and washing into
the combined sewers, drainage ditches and into our waterways, no
different from fertilizing your lawn. The same is true for the living
walls, no matter which growing media is present, fertilizer is going
to have to be added and will eventually contribute to runoff.
Recently I became aware of a medium designed from a fermentation
process using old shipping containers that is providing high quality
fibrous compost with a consistent organic nitrogen content of 3%
using chicken manure as the key ingredient. (Chicken manure
has been documented to leach into the water table causing harmful
effects because of the concentration when not removed or used as
a by-product.) The end product results in a concentrated N,
P, and K mix enhanced with additional micronutrient rich media,
while the process removes 100% of the methane off-gasses.
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Fermentation
process in old shipping containers.
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The process
creates a compost and bio-fertilizer being used as part of the new
living wall growing media. These properties provide a benefit
for the green wall and roof market because it will eliminate the
use of synthetic fertilizers and it will not leach like the synthetics.
There is no runoff so it becomes the organic base to the advanced
living wall and roof media, and can be used as a top dressing to
all green roofs to replenish the nutrient values. For green
walls, a tea comprised of the fermentation is introduced to the
irrigation providing some of the highest quality of living
wall media available.
So, what is my answer to the ever popular question, “What about
the growing media?” Now you can see why I answer, “What about
it?”
Green walls are advancing; the means in which we secure plants to
the wall are numerous. The novelty is over and living wall
projects are taking on awe inspiring displays of art, function and
controversy. And questions of liability, construction, and
maintenance are still part of the unknown equation. I know
that the skills of many trades are needed and the skill set
needed cannot be seen as a standalone trade.
I believe change is good and advanced technologies will continue
to grow, and liability issues will decrease with increasing levels
of education and experience. I also believe that the next
wave of fertilizer-free growing media for both walls and roofs is
close to being commercialized. No matter what, the industry
has expediential room for growth and advancements, keeping us all
busy for quite a while.
George Irwin, The Green Wall Editor
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.
Past Green Wall Articles
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