What information can you give me on rooftop gardening?

T.M.VermontAnswer: I am pleased to provide you with information on rooftop gardening.Rooftop gardens are a unique way to use unused and sterile spaces for food production. There are many different types of rooftop garden systems that can include growing crops in containers, in raised beds, or even greenhouses. Rooftop gardens not only provide food, but also help cool buildings and can improve air quality. Below is an excerpt from an article that was written by two rooftop gardeners in Canada. The garden is part of a university and is located on the roof of an academic building. The authors discuss the many benefits of producing food on roofs, but also share many of the problems and mistakes that they experienced during their growing season. The section of the article that is cited below begins by comparing the differences between traditional food production systems and growing crops on roofs. The main differences can be summed up in two words: sun and wind. The resulting growing conditions tend to be more extreme (1). Even after a good rain, it takes very little time for the beds to dry out; our solution is mulch, mulch and more mulch. Even so, not everything grows well on the roof. In particular, we have difficulty with spinach, peas and beans. Other heat-loving plants, however, do very well including tomatoes, peppers and basil.Another significant limitation on the roof is soil fertility. In the spring we recruit unsuspecting (or very generous) volunteers to help us haul compost from The Spoon. We further amend the soil with sheep manure from Tom’s farm, green manure and compost tea. In particular using green manures or compost tea is labour-saving, because it precludes the need to bring more materials up to the roof through the Environmental Sciences Boardroom (the only access to the roof).Despite these challenges, rooftop gardening provides a number of incentives. We need not worry about pests such as deer. Furthermore, what is a challenge in the summer – namely the warmer, dryer conditions – is an advantage in the spring when we’re able to start gardening a few weeks earlier than the surrounding area. Thus the rooftop climate acts as a season extension.Fortunately for us, the rooftop garden was a part of the initial building design. Thus, not only is there proper irrigation and drainage, but the building has sufficient load-bearing capabilities to support eighteen inches of saturated soil. To prevent water and roots from compromising the roof there is an impermeable membrane beneath the soil. The garden acts as a temperature moderator for the building below, cooling it down in the summer and insulating it in the winter.On a larger scale rooftop gardens and sod roofs can do the same in a city. A recent study prepared by Ryerson University for the City of Toronto, found that green roofs significantly reduce stormwater runoff, reduce energy consumption and the reduce the heat island effect. Furthermore, they help to beautify the city and create more natural green spaces in urban areas – for everyone, including the black swallowtails.Tips for Rooftop GardeningMulch everything.Water deeply and often.Choose vegetables that suit the environment.Use compost tea and green manures to ammend the soil.Attempt to create shade, with trellises for example.If you don’t have the means for an intensive rooftop garden consider using containers.Referenced below are several articles on rooftop gardening. There are also a few websites posted below that provide further information. One website posted below (http://rooftopgardens.ca/en) is for the Rooftop Garden Project. This collaborative organization has recently published a manual titled “Guide to Setting Up Your Own Edible Rooftop Garden.” (PDF/2.28MB) This publication contains over 80 pages and is available to download from the website. If you are unable to download the publication, it can be obtained by contacting the organization Alternatives by telephone at (514)982-6606 x2230. References:(1). Blyth, Aimee and Leslie Menagh. 2006. From Rooftop to Restaurant ? A University Caf? fed by a Rooftop Garden. British Columbia, Canada: City Farmer.Resources:Price, Martin. 1992. The Eave Trough Garden. North Fort Meyers, FL: ECHO.Price, Martin. 1992. The “Wick” Method of Rooftop Gardening. North Fort Meyers, FL: ECHO. Voelz, Jan. 2006. The Characteristics & Benefits of Green Roofs in Urban Environments. Davis, CA: UC Davis Extension. Wilson, Geoff. Date unknown. Can Urban Rooftop Microfarms be Profitable? Netherlands: RUAF.Web Resources:Community Food Security Coalitionhttp://www.foodsecurity.orghttp://www.cityfarmer.org/subrooftops.htmlhttp://www.foodshare.net/toolbox_roof01.htmThe Rooftop Garden Projecthttp://rooftopgardens.ca/enGreen Roofs for Healthy Citieshttp://www.greenroofs.org