In built out cities, like San Francisco, Vancouver, Seattle and New York City, land is difficult to come by for urban agriculture. However, many cities are discovering an untapped resource: rooftops. In December, New York City’s Department of City Planning proposed a zoning amendment that would exclude urban agriculture operations, such as greenhouses, on commercial buildings from certain height and floor-area restrictions. On April 30, 2012, the New York City Council approved the Zone Green Text Amendment. The amendment allows greenhouses to be “exempt from floor area and height limits, provided that it is located on top of a building that does not contain residences or sleeping accommodations. These greenhouses must not exceed 25 feet in height, must set back six feet from the roof edge, and must include practical measures to limit water consumption.”

According to a recent study by the Urban Design Lab at Columbia University, there is over 3,000 acres of rooftop on commercial and industrial buildings in New York City that is potentially suitable for urban agriculture. For more information, visit the links below:

• The Potential for Urban Agriculture in New York City (Urban Design Lab, Columbia University)
• Zone Green Text Amendment (New York City, Department of City Planning)
• Growing Rooftop Farming in NYC (Urban Food Policy Blog, January 25, 2012)
• Opening the Door to More Rooftop Farming (State of the Planet Blog, Columbia University, February 3, 2012)
• Huge Rooftop Farm is Set for Brooklyn (New York Times, April 5, 2012)