The following is excerpted from Eat Up: The Inside Scoop on Rooftop Agriculture, recently published by New Society Publishers.
Each rooftop farm and garden, no matter how small, can enhance the lives of individuals and communities as people are drawn inward and upward. From human and social health benefits to environmental improvements, economic advantages to enhanced food access, rooftop agriculture enables and empowers people to make their communities healthier, more enjoyable places to live.
Existing rooftop
Artistic rendering
health benefits
As with ground-level urban agriculture, food grown on roofs is as fresh as it comes. The nutrients of many fruits and vegetables degrade with time once they are harvested, which means that eating fresh food gives your body the nutrients it needs to take care of you. Rooftop produce is generally grown using chemical-free or even organic prac- tices, which is great news because avoiding exposure to chemical herbicides, pesticides and fertilizers further contributes to a healthy body. Exposure to these fresh, diverse foods also encourages healthy eat- ing habits, which is particularly important for children, who often shape their eating habits at a young age. Healthy eating habits (combined with regular exercise) also help combat adult and childhood obesity. A 2012 report from the US Department
Growing fruits and vegetables yourself offers another set of benefits. Rooftop farmers and gardeners are regularly exposed to fresh air, sunshine, exercise, all of which promote an overall healthy lifestyle. Many farmers and gardeners also report a sense of satisfaction and calm after working the soil. Rooftop agriculture creates healthy, happy people.
social health
Furthermore, fostering relation- ships with rooftop farmers is essential in strengthening the local food system. People are much more likely to make healthy food choices and support local growers if they have access and exposure to farms and gardens. Building more urban farms and gardens, whether on the roof or the ground, provides children and adults alike with more opportunities to experience food production first-hand, make healthy, well-informed food choices and ultimately reconnect with their food.
Practically speaking, rooftops provide space for food production when no ground-level landscape is available.
Another social health benefit of rooftop agriculture is the provision of green space, which is critical for building healthy communities. An article published in the Journal of Epidemiology and Human Health found that, for over 250,000 adults and children tested, perceived general health increased with the percentage of green space within the immediate living environment.2 Another study by the same author found that 15 out of 24 physician-diagnosed disease clusters were less prevalent in test subjects living in close proximity to green space.
Diagram showing the overlapping benefits of rooftop agriculture with urban agriculture and green roofs
environmental benefits
Rooftop farms and gardens mitigate stormwater runoff, particularly when soil-intensive strategies (such as row farm- ing) are implemented. All this soil takes the place of bare membrane roofs, which rapidly drain particulate and pollutant- filled stormwater into the sewer system, ultimately draining into our rivers and streams. Rooftop soil and plants absorb this stormwater, dramatically slow its flow into the sewer system (thereby reducing “peak flow”) and filter many contaminants from the water. Interestingly, most rooftop agricultural soils retain more stormwater than traditional green roofs, because agricultural soils contain more organic material, which absorbs and holds more water, than green roof media.
Urban plants are also applauded for their ability to filter particulate, or small grains of wind-borne sediment and dust, from the air. The leaves themselves absorb most of the particulate, which means that rooftop farms and gardens installed next to elevated highways, active factories or other point-source pollution centers may lead to a particulate-filled salad! Plants also provide the invaluable service of releasing oxygen and water vapor from their leaves. The release of water vapor is particularly important in cities, because this moisture cools the air around the plants. Water held within the soil itself is also critical in moderating microclimate, as water gains and loses heat much more slowly than bare membrane roofs and even the surrounding air. As a result, installing rooftop farms, gardens and green roofs on a city-wide scale can actually reduce the city’s overall temperature. Scientists refer to the phenomenon of city- wide cooling as heat island effect reduction.
Rooftop row farms are also advantageous in their ability to provide insulative value to the building below, which reduces a building’s utility usage and therefore the amount of fossil fuels needed to heat and cool the building. Since build- ing insulation is a function of roof area to building volume, rooftop agriculture provides the greatest insulative benefit to large one to two-story buildings. Industrial buildings and big box stores see the greatest insulative benefit, as evi- denced by data obtained by Roofmeadow (the green roof firm where I work), from Walmart Store No. 5402 in Chicago, the world’s largest green roof study site.
Lastly, reducing the distance that food travels to reach your plate decreases fossil fuel use, air pollution and packaging. Most rooftop farms and gardens further reduce their fossil fuel consumption by avoiding the use of chemical fertilizers, pesticides and herbicides. In the words of Ismael Hautecur, Project Coordinator of Montreal’s Rooftop Garden Project, the greatest environmental impact of all is changing people’s habits.
A chef on his Portland restaurant’s rooftop, Noble Rot, OR
photo by John Q. Porter, courtesy of Noble Rot
economic benefits
Buying locally produced farm goods keeps money within the local economy, and for densely built cities that lack ground- level gardening space, rooftop agriculture may be as local as it gets! In 2003, the Maine Organic Farmers and Gardeners Association estimated that if every family in Maine spent $10 per week on local food, $104 million would enter the local economy each year. This incredible statistic proves that we have the power to strengthen our local economy through strategic purchasing. Buying locally also increases the circulation speed of money, which means that dollars pass through many hands during a short period of time, thereby benefiting more people more quickly than when non-local goods are exchanged.
Rooftop agriculture also benefits the local economy by creating jobs, and at times, the need for green jobs train- ing. Full-time urban farming positions may be particularly appealing to young professionals who want to work in an agrarian setting, but not at the sacrifice of an urban lifestyle. Rooftop hydro- ponics offers additional employment opportunities for highly trained techni- cians and researchers, as well as blue collar (or “green collar”) workers.
Studies have estimated that, on average, produce travels 1,500 miles from field to plates in Middle America.8 Shipping food great distances requires a middleman, who generally transfers the costs of packaging and shipping to the consumer. These costs fluctuate with fuel prices, which means that buying locally results in more stable food prices. Buying directly from farmers takes things one step further by eliminating the middleman and putting more money in the pockets of the men and women who are growing your food!
Rooftop agriculture may result in additional economic benefits to homeown- ers and renters, who can save money by growing their own vegetables and herbs at home. Schools, universities, restaurants, markets and even office buildings may similarly benefit by reducing their food purchase. Additionally, restaurants in par- ticular may be able to grow specialty items, which would be prohibitively expensive to buy. The sale of food grown on location can also bring in business, and may enable ad- vertising that can increase sales. In regions where these types of products are a novelty, the restaurant or store may be also able to charge higher prices for these highly desirable specialty items. Owners of multi- unit residential buildings may also benefit economically, by converting underutilized roof space into garden plots. In Singapore, some building owners rent these garden plots to tenants, a similar concept to charg- ing monthly fees for a parking space, gym access or any other building amenity.
In general, building owners may be able to additionally benefit from subsidies and tax incentives directed at green roofs or urban agriculture in certain cities. Owners and tenants of one or two-story buildings may also experience utility savings associated with the insulative value of certain types of rooftop agriculture.
Farmer Annie Novak and her apprentices stocking an onsite farmstand, Eagle Street Rooftop Farm, NY
City planners and food justice advo- cates routinely promote urban agriculture as a means of increasing food access within cities. When vacant lots and park land is unavailable for farming and gardening, though, rooftops and balco- nies may provide the only available real estate for hungry growers. In addition to space, access to information is integral
Food access is a social justice issue; it is a human rights issue. When urban communities lack access to affordable nutritious food, we must collectively help our fellow community members, and also educate and empower them to help themselves. Rooftop agriculture provides the canvas for food access assistance and empowerment in cities across North America. Government and non-profit food aid programs may take years to get off the ground, and may not provide fresh produce once they are fully functional. Rooftop and ground-level gardening can start today, and the bounty is delicious.
A low-income neighbor volunteering in exchange for fresh produce, SHARE Food Program, PA
Top image by David Barrie, courtesy of Creative Commons licensing.
