
Kyle McCroy grows organic lettuce and basil on an urban farm.
Viraj Puri climbs three floors of a gritty industrial building in Brooklyn to the daily grind of his early-stage start-up--negotiating deals with big customers, keeping up with new technology, meeting with investors and making plans to expand. But Puri's 20 employees aren't trying to build the next big social-media or clean-energy company. Instead, on a rooftop in the Greenpoint neighborhood, they run a small urban farm, Gotham Greens, a sleek and sunny oasis of leafy lettuces and herbs.
At the company's 15,000-sq.-ft. hydroponic greenhouse Gotham Greens grows plants in mineral-infused water instead of dirt, using software that closely controls temperature, irrigation...