It’s a 1-acre farm fertile enough to produce a 2-ton harvest of rainbow chard, kale, basil, eggplant and cucumbers -- and it sits atop an 11-story industrial building in the Brooklyn Navy Yard.
New York City’s largest rooftop garden will soak up more than 1 million gallons of storm water a year, reducing the risk of sewage overflow into the harbor when runoff exceeds the system’s capacity, officials said. The water will be used to irrigate the crops, and the soil will provide better insulation for the building than traditional black roofs.
It’s part of Mayor Michael Bloomberg’s two-year-old strategy to reduce emissions of climate-changing carbon gases 30 percent by 2030. The so-called green roof will create jobs and “help keep our harbors and streams clean,” Bloomberg said in a statement prepared for a group of officials and reporters who planned to tour the site today.
The farm’s 12-inch-deep growing beds are composed of a non-dirt-based soil formula engineered for rooftop use by Skyland USA LLC, an Avondale, Pennsylvania-based manufacturer, under the specifications of the Brooklyn Grange, a nonprofit operator of farms atop roofs of two buildings in Long Island City, Queens, and at the Navy Yard.
It’s the Brooklyn Grange’s second farm. In addition to leafy greens, the organization representatives say they intend to grow aromatic herbs, heirloom tomatoes and carrots from April to November, with cover crops such as clover in winter to prevent erosion and to replenish vital nutrients.
Brooklyn Grange sells its produce to local stores, markets and restaurants and sometimes to tenants of buildings below its rooftop farms, the group says on its website.
The Navy Yard also is home to the Brooklyn Grange Apiary, more than 30 beehives that will yield about 1,500 pounds of honey a year, the mayor’s office said.
The Navy Yard and Brooklyn Grange created the farm with a $592,730 grant from the city Department of Environmental Protection as part of the NYC Green Infrastructure Plan. The program uses vegetation, soil and other elements to absorb and evaporate water to manage storm water and improve the quality of the city’s surrounding harbors and rivers.
To encourage installation of green roofs, the city provides a property-tax abatement of $4.50 per square foot of green roof, up to $100,000. Property owners qualify with installation covering at least 50 percent of a roof, and a maintenance plan to ensure viability of the vegetation and storm water benefits. The program is currently scheduled to remain in effect until 2013, the mayor’s office said in a news release.
On the Roof
New York City receives about 43 to 50 inches (109 to 127 centimeters) of precipitation per year with little variation from month to month.
About 78 percent of the city’s urban surfaces -- including rooftops, sidewalks, streets and open space -- are impervious, meaning water is unable to infiltrate the ground or get absorbed by trees and other foliage, according to the DEP’s website. Rooftops make up about 28 percent of the city’s impervious surfaces, according to the department.
The mayor is founder and majority owner of Bloomberg News parent Bloomberg LP.