Eric Haley, Jennifer Nelkin, and Viraj Puri, on the future site of Gotham Green's first garden. [Photographs: Jennifer Nelkin]

Jennifer Nelkin believes that the future of high-end, boutique-quality farming is not in California, sunny Florida, or even the fertile soils of the Hudson Valley. It's right under our noses. Or more accurately, right above our noses.

As co-founder of Gotham Greens, New York's first commercial rooftop hydroponics operation, Jenn's got a lot riding on that future. "I really hope that rooftop gardening is a successful venture, because we've borrowed $1.4 million to try and find out."

Located on the roof of a manufacturing plant in Greenpoint Brooklyn, and equipped with solar-powered pumps that feed nutrient-enriched rainwater to an acre of greenhouse space, Jenn's goal is to produce greens and herbs to sell to local chefs, retailers (Whole Foods has expressed interest), and direct to the public by as early as this fall.

So how does one get involved with a project like this?

I first met Jenn a few months ago at a dinner party that my friend Joshua Levin of GoodEater.org and I threw for few local food superstars (including our very own Erin), where she regaled us with stories about greenhouses on Mars.

Wait... what? Greenhouses on Mars, did you say?

That's right.

After completing her MS in Plant Sciences from the University of Arizona, she was approached to work on martian greenhouse program for NASA. "It was a natural fit," she said. "Working in Arizona, you've got a very specific set of conditions. It's a fantastic environment for growing food because of the light." Crop yields are remarkably closely linked to available light—a 1% increase in light will reliably lead to a 1% increase in crop output. The problem is water. "To farm in Arizona, we were forced to use the most water-efficient means possible."

The efficiency of closed-system hydroponics, in which plants are grown directly in nutrient-enriched water that is carefully cleaned and recycled back into the system makes it an ideal candidate for martian farming. "It saves you from requiring a fresh water source. Transporting heavy water into space is expensive."

Turns out that despite its innate awesomeness, martian greenhouses are still a ways off (the plans have since been revised to apply to lunar situations). But the lessons learned from designing them were invaluable to Nelkin.

"Suddenly, I had built this niche for myself of designing extreme greenhouses." Her next project was actually completed: a greenhouse at the South Pole with year-round production. "Hydroponics turned out to be the perfect solution again for the South Pole. There's an international treaty that prevents any country from transporting their own soil to the pole. Hydroponics doesn't need any soil."

"Antarctica is basically closed for six months out of the year. That means that whoever's down there, stays down there." There are no ships, no airplanes, no supply drops, nothing." People rely on canned, frozen and dry food, and it's dark all the time."

In situations like that, greenhouses have as many psychological benefits as they do nutritional. "The researchers can go into a brightly lit, humid environment, with plant-based smells. You have no idea how important that humidity, light, and scent is until you are deprived of it."

Turns out that every one of the benefits of lunar and Antarctic hyrdroponics make perfect sense in an urban setting, where access to natural resources is limited, and well lit, green spaces are in short supply.

In addition to using approximately 90% less water than traditional soil-based farming, greenhouse-based hydroponics also offer consistent, year-round yields, making planning such an unprecedented business a little more reassuring. "With soil farming, your crop yields have to do not only with light, but with soil quality and pests. Hydroponics cuts those variables out."

But the real question: aside from appealing to the bearded, DIY, Brooklyn hipsters or yuppie environmentalists high on good intentions but low in actual information, is there really a reason to build greenhouses in the city?

Flavor

According to Jenn, some of the answers are obvious. "As far as flavor is concerned, there's no question that vegetables grown right in your backyard are vastly superior to ones that have even been shipped as far as the farmers' market." Most supermarket vegetables are picked under-ripe to help them withstand the rigors of shipping. And "even if the vegetables are picked completely fresh, they begin to lose quality as soon as they are removed from the vine."

"Hydroponics has gotten a bad wrap, mostly from those awful hyrdoponic tomatoes you see in the supermarket." With a commodity crop being sold wholesale to large supermarket chains, appearance and yield are the chief considerations for growers. "Those tomatoes are given more water than they need to grow in order to bulk up their weight and increase profits. That's why they taste so bad."

"Every farmer knows that stress-related events often lead to the best tasting fruit. I can artificially starve my tomatoes of water. The tomatoes respond by producing more sugar through photosynthesis." Flavor and nutrition, she explains, relies on two factors: was it picked ripe and eaten fresh, and did the tomato have the nutrients it needed while growing?

"A tomato grown in nutrient-deprived soil will definitely taste worse than a tomato grown in good soil, or in a well-designed hydroponic system. My yields are smaller than Canadian commodity hydroponicsa, but they're as good as the best tasting tomatoes you've ever had." By selling directly to niche markets, Gotham Greens will be able to charge higher prices for customers who are more concerned with flavor than size, rather than being tied to the whims of the commodity market.

Social and Environmental Impact

"A lot of people think that urban farming is the answer to some problems with the environment," says Jenn. But it's just a knee-jerk reaction. "In reality, pretty much no data exists on how efficient, or how good for the environment urban farming really is."

Part of the goal of Gotham Greens is to have as minimal an environmental impact as possible. The facilities will run largely on rain water and solar energy. It seems impossible that it won't be more efficient than a large-scale operation which relies on massive water, energy, and fertilizer use, right? "It's not that simple. There's trucking, shipping, different kinds of production method. We're still at the stage that we need to collect more data to see if it's an environmentally responsible means."

"We get calls non-stop from everyone who wants to build an urban farm. I'd love to be able to tell them with confidence—to automatically say, 'This is right. This is the answer,' but until we have the numbers, nobody really knows."

That's not to say that there aren't other less-edible benefits. "Most people need green spaces to be happy." Whether it's in the form of community-based gardens, cities, educational gardens (before launching Gotham Greens, Jenn worked on the Science Barge project, an educational floating greenhouse on the Hudson River), or commercial projects like Gotham Greens, cities will always need their green space. "And that's a really fantastic thing."

Jenn, if you ever need a 400-square-foot plot with year-round shaded growing space next to a construction site and an elevated subway, my deck is all yours.

About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.