Until the mid-nineteenth century, most of New York City was farmland. Now, thanks to the constant drumbeat of locavorism, some of it is going back to seed. Urban horticulture has long been practiced at hundreds of community gardens around the city. But a new class of growers is more concerned with bolstering a sustainable food system and, if possible, turning a profit than with cultivating a peaceful vegetable plot. In studiously trendy neighborhoods like Red Hook, Greenpoint, and Long Island City, the farming is done on rooftops and old basketball courts, mostly by the young, idealistic, and educated. Some still follow the old church-pantry model, but others are more entrepreneurial, relying on restaurant sales and CSA (community-supported agriculture) subscriptions to turn farming into a viable business. Here, a portfolio of the city’s most prolific food producers, and a map of where to find them.