Rooftop farming is the practice of cultivating food on the rooftop of buildings. Rooftop farming is usually done using hydroponics, aeroponics or air-dynaponics systems or container gardens. Besides using the allready present space at the roof itself, additional platforms could possibly be created between high-rise buildings called “aero-bridges.
Food production:
The sustainability of urban systems can be significantly bolstered by fostering a more urban agriculture. The average American meal travels 1500 miles from field to table, using 10 times more energy than the caloric value of the food itself. This represents an incredible environmental cost in fossil fuel emissions, pollution associated with extraction, and loss and division of natural habitat by asphalt, to name a few of the more direct costs. Less direct are the costs of the industrial agricultural system required to maintain the artificially low cost of that well-travelled meal. These include environmental costs associated with high-input monocultural growing methods as well as social and health costs for the local rural community and farm workers. Unless alternatives are sought to this global sourcing of food without regard for externalized costs, rising urbanization will continue to be accompanied by increased environmental and social costs.
Rooftop agriculture is one way in which urban areas could attempt to be more balanced and sustainable in their resource consumption. It is possible to produce a variety of fruit, grain, and vegetable crops on rooftops, either in containers or as field crops.
Chicago’s recent regulation:
Chicagoans may soon witness the transformation of the Windy City’s skyline from bare, unused rooftops into green fields of lettuce, herbs and vegetables.
The Chicago City Council’s zoning committee passed regulations Thursday that sanction the use of rooftops in commercial districts for growing and selling produce. Previously, the committee only gave special permission on a case-by-case basis.
“This means that green roofs, which have enormous benefits to the community, can now create financial benefits,” said Molly Meyer, owner of Rooftop Green Works LLC.
Meyer, who has been designing and installing green roofs for over four years, said a 12,000 square-foot rooftop – equivalent to two and a half basketball courts – can produce 20,000 pounds of vegetables a year. She predicts this would translate into $25 of revenue per square foot. Given the estimated $15 a square foot cost involved in rooftop farming, Meyer calculates that investors could be fully paid back in five years.
Link to full article:
http://news.medill.northwestern.edu/chicago/news.aspx?id=186821
Addtionial reading:
http://www.cityfarmer.org/greenpotential.html
http://noimpactman.typepad.com/blog/2008/06/urban-rooftop-f.html
Link:
http://www.youtube.com/watch?v=PwPGxHlqLtE
I am working on some more stuff on green roofs. So check back often. In the meantime beware of tomatoes on your next vertical vent job! LOL 
Stay Safe
Lt. John Shafer
