For decades, a sprawling steel mill in Baltimore, Maryland was a key site for American industry, making steel for World War II battleships and the Golden Gate Bridge. By the year 2000, however, the industry was failing, and site owner Bethlehem Steel declared bankruptcy. Now, one corner of vacant land at the former mill will become an indoor farm growing pesticide-free lettuce in a sensor-filled greenhouse.

"I think what we're doing is sort of representing 21st-century manufacturing," says Viraj Puri, co-founder and CEO of Gotham Greens, the Brooklyn-based urban agriculture company building the new greenhouse. "This, at one point, was the largest steel-producing facility in the world. It employed tens of thousands of people. Those jobs disappeared when the global steel industry changed . . . we're coming in and helping to revitalize [the economy] and produce jobs that represent this innovative, technologically advanced way to produce food."

In New York City, the company pioneered using large rooftop greenhouses to grow greens with no soil, no pesticides, and far less space and water than traditional farming in fields. Most lettuce, grown in areas with limited water like Arizona and California, is shipped thousands of miles to consumers on the East Coast. Gotham Greens, like other startups in the urban farming space, wanted to offer consumers fresher produce that used fewer resources.

After opening its first Brooklyn greenhouse in 2011, the company built another on top of a local Whole Foods. A third greenhouse, in Chicago, sits on top of a sustainably designed factory on a former brownfield. A second Chicago location, next to the first, will be complete by the end of this year.

Gotham Greens Chicago [Photo: Julie McMahon/Gotham Greens]

In Baltimore, as in the other cities, the company will provide both low-skill farming and packing jobs and high-skill jobs in horticulture and engineering. The site, now run by a company Tradepoint Atlantic, will now include a mix of occupants rather than a single industry (Tradepoint Atlantic is the fifth owner since the steel mill closed in 2000; the first four tried to revive steel manufacturing there, and failed.) UnderArmour and FedEx will use the site for distribution, and others are using it for vehicle importing. But Gotham Greens represents a different type of industry.

It won't be the first indoor farm at a former steel industry site. In Newark, New Jersey, the vertical farming company AeroFarms grows baby greens where a former steel factory once operated. Because the farms use hydroponic systems–growing without soil, indoors–it's possible to grow anywhere, including on the ruins of heavy industry.

The new greenhouse in Baltimore will create 60 jobs. That's far fewer than the 30,000 jobs the former steel plant provided at its height in the middle of the 20th century (though steel mills now use only a tiny fraction of the labor they once did). Puri says that the operation in Baltimore could triple over time–and all of the new businesses at the site will create a total of 9,500 permanent, full-time jobs.

The company also plans to continue expanding to other cities, albeit slowly. "We are producing a lot of lettuce," says Puri. "We're doing about 20 million heads a year. So we're definitely large-scale at this point. But in order to maintain product quality, consistency, and food safety, which is incredibly important, we didn't want to rush into opening more facilities than we thought we could effectively, efficiently manage. It's a measured, step by step approach. We're assessing sites in other cities as well. Our vision is certainly to have a network of urban greenhouse farms in cities throughout the country."