Viraj Puri, 31, is co-founder and chief executive officer of Gotham Greens, an urban farm on a warehouse rooftop in the Greenpoint neighborhood of Brooklyn, N.Y. The farm is part of a growing movement. As world populations swell, particularly in major cities, scientists and public officials believe urban farms will play an important role supplementing our food supply.

Photograph by Will Halsey for Bloomberg Businessweek

Viraj Puri, 31, is co-founder and chief executive officer of Gotham Greens, an urban farm on a warehouse rooftop in the Greenpoint neighborhood of Brooklyn, N.Y. The farm is part of a growing movement. As world populations swell, particularly in major cities, scientists and public officials believe urban farms will play an important role supplementing our food supply.

Photograph by Will Halsey for Bloomberg Businessweek

Gotham Greens: A Farm Grows in Brooklyn

Viraj Puri, 31, is co-founder and chief executive officer of Gotham Greens, an urban farm on a warehouse rooftop in the Greenpoint neighborhood of Brooklyn, N.Y. The farm is part of a growing movement. As world populations swell, particularly in major cities, scientists and public officials believe urban farms will play an important role supplementing our food supply.

Photograph by Will Halsey for Bloomberg Businessweek

The rooftop in Brooklyn. The solar panels account for more than 50 percent of electricity used.

Photograph by Will Halsey for Bloomberg Businessweek

The front door to Gotham Greens’ greenhouse.

Photograph by Will Halsey for Bloomberg Businessweek

Seedlings germinate in small square clusters called propagation flats.

Photograph by Will Halsey for Bloomberg Businessweek

After a short period of growth, they are transplanted to the "fields" in the greenhouse.

Photograph by Will Halsey for Bloomberg Businessweek

Green leaf lettuce grows before being transplanted to the hydroponics.

Photograph by Will Halsey for Bloomberg Businessweek

Empty hydroponic troughs await new seedlings. Crops are harvested daily for fresh delivery and a high rate of production.

Photograph by Will Halsey for Bloomberg Businessweek

At 15,000 square feet, the greenhouse is the largest of its kind in the country.

Photograph by Will Halsey for Bloomberg Businessweek

The climate-controlled greenhouse is monitored by a computer system that can change the temperature by opening vents in the ceiling. When it's raining, the system knows to open the side vents.

Photograph by Will Halsey for Bloomberg Businessweek

Gotham Greens employs 20 people and yields the same amount of produce as a 6- to 7-acre soil farm.

Photograph by Will Halsey for Bloomberg Businessweek

Baby butterhead lettuce.

Photograph by Will Halsey for Bloomberg Businessweek

The rooftop on which the greenhouse sits. Changes in New York City's zoning code allow more rooftop farms, which should foster industry growth.

Photograph by Will Halsey for Bloomberg Businessweek

Gotham Greens sits atop this building, which once was a bowling alley but now houses many businesses.

Photograph by Will Halsey for Bloomberg Businessweek

Gotham Greens produce is sold in the New York City metro area at Whole Foods and Union Market, among other stores, and through Fresh Direct.

Photograph by Will Halsey for Bloomberg Businessweek