Sunday, June 26, 2011

Growing Food on Roofs - Rooftop Permaculture Can Help Feed the Urban Core

Green Roof Mat with Swale Pads For Food Growing - Roof Permaculture
Growing food on the roof makes sense.  With hundreds of thousands of acres of otherwise wasted space available for planting in the Urban Core, city dwellers are now more than ever planting their rooftop spaces to help offset high food prices.

The rooftop permaculture systems we work with generally employ some type of three dimensional weave to allow plant roofs the chance for anchoring.  These are the same systems we just successfully tested in the hurricane simulators - where, once installed the plants and soils stay embedded in the mats under 120 mph winds.

Soil embedded three dimensional netting, though not essential, is important in sub tropical climates influenced each summer by cyclones and hurricanes, helping hold both soil and plants in place.  The weave also allows for steeply sloped rooftop areas to be taken advantage of for agricultural purposes.

Green Roof Mat & Soil Added For Food Growing - Roof Permaculture
Low cost and organic alternatives to the polypropylene weave include hemp and burlap fabric, fowl or hail netting, twine weave and any other system allowing inter-connectivity of plant roots to underlying roofing systems.

Importantly, growing food on the roof creates economic opportunity.  Many small cafes and restaurants will purchase locally grown organic produce.  Moreover, rooftop gardens  reduce heat island effect, produce oxygen and sequester carbon, provide habitat and offer many other benefits.

One of the first suggestions a friend offered was to take the multi-dimensional mat and fold it under in certain areas, creating a swale-like structure - a technique successfully used in permaculture practices, one with a focus on water efficiency maximization.

Judy's Spring Mix Ready for Green Roof Planting

The folds were added after the fact because the mat had already been installed.

A lightweight roof soil mix was added to the mat and seedlings Judy had grown - a spring mix - were planted.

Growing food on roofs and walls in the Urban Core opens many economic, ecological and social doors.  Elimination of food transportation costs can even help reduce our dependence on foreign oil.

Green Roof Food Garden - Roof Permaculture


Alejamuel Sultz said...

Using your roof to grow food is a brilliant idea. The urban landscape will take on a new look if this practice becomes widely accepted. I can just imagine what the city would look like with roofs brimming with produce.

Anonymous said...

With current green roof technologies, growing food crops on roofs will most likely cause more problems than good. In order to grow any worthy crop in roof microclimates requires heavy fertilization. These high concentrations of nutrients will then be apt to leach out of soil in stormwater adding to pollution to local watersheds. The ability to mitigate storm water run off/nutrient leaching is one of the primary benefits of green roofs. All we would be doing is trading the benefits of the latter for local food production. I like where your heads at and the fact that people are thinking about this but there is a lot more research that needs to be done in order to make this a viable option