Green Roofs For Fun & Food & Learning - Garlic Boards!

Kevin's Florida Green Roof Garlic Board

OK - its not the highest tech approach to trying out new systems on a green roof but it is an approach I've used for years and it works!

Place a small 'pilot-plant' or 'test-unit' on the roof and see if the plants thrive or if the plants die.

Here is the sustainable Garlic board.

Sustainable because though this example is cedar, the board can be made of pine (potentially sustainable) or of bamboo (even more sustainable).

What does this really have to do with green roof?  Sure, it may be small scale permaculture on the roof but it doesn't have a water proofing system or root barrier system and one can imagine what kind of missile the contraption may become during 130 mph winds of a tropical cyclone here in Jacksonville - though the last really large hurricane to hit Jacksonville was Hurricane Dora in 1964.  Yet Jacksonville was hit by 18" ( 450 mm ) or heavy rain in 2008 by Tropical Storm Fay - if you are interested in seeing a video I shot during TS Fay of how 60 mph gusts only ruffles the tops of green roof plants - click below.

2008 TROPICAL STORM FAY GREEN ROOF VIDEO

We'd take the board off the roof if a hurricane was approaching.  Thankfully, hurricanes or tropical cyclones give at least a couple hours notice or more now thanks to NOAA and other weather watch services.

However hurricanes are not the focus of this post.

The board is a statement of sustainability.

The garlic board is a first step in a process.  A process of moving away from synthetic materials to more natural materials for green roofs.  Surely there will be hundreds, if not thousands of other trial materials in our search for green roof sustainability.

We also purchased a roll of burlap from the hardware store this week and it too will be somehow fashioned into a type of 'garlic board' and tested.

Joanie Regan, the stormwater manager for the City of Cocoa Beach, has always told me that she is wary of putting 'plastic' into the ground.  She refers to the many stormwater systems available on the market made from polypropylene and other relatively stable petrochemical based stormwater products.  Her statement has resonated with me over time.  I keep thinking that I should be wary too, of installing layers of 'plastic' on roofs to create natural habitat.

Our collective intelligence as humans across the globe is so great that maybe if we throw out an idea, the idea will catch hold somewhere and grow.

The idea of developing a natural materials based green roof is growing in my mind and the garlic board is just one small step towards the idea becoming reality.

And the garlic board is working.  The cloves are sprouting now and hopefully will grow and fill out the deep wide holes drilled into the board under the trough filled with soil visible in the photograph.  Certainly the garlic is up high enough in the air to enjoy the bright sun's rays and the system is soaked with morning's dew on some mornings.

So we will watch the garlic cloves and learn something about cellulose as a platform for growing plants on roofs.

Having worked hands on with plants for over thirty years I believe there are approaches to take in developing and growing large mats of root interwoven plants that would hold themselves together on a green roof.  Though wood and burlap and other natural materials may disintegrate over time, they may provide enough of a structural system to allow the plant roots to develop into a sustainable structural system themselves.

Coir may be another sustainable material for green roof system establishment.  Potassium, salt and other limiting issues with coir can be resolved with pre-treament and maintenance procedures.

The approach we are discussing here would be relevant to green roofs with a primary function of habitat creation, food production, O2 production, carbon sequestration, urban heat island effect yet may present problems with green roofs constructed primarily for stormwater issue resolution.

Though a topic for another blog post, green roofs created for stormwater attenuation will probably need to be constructed out of a long term stable material.


True sustainability is what we all strive for.

I may never stop using woven plastics such as polypropylene or polyethylene, especially if they are made from post-consumer recycled plastics - might as well use up the scrap and they do hold the roof plant material together quite effectively.

However we are in peak oil, plastics are petro-based and I am a dreaming product of the post-hippy 1970's plastic junk inundation era.

I do want to make a long term difference.

And maybe the start lies with what I will learn from a cedar board on a roof with allium plants.

Plastic?

As always, email your comments and questions.

Happy Green Roofing!

Kevin