Sept. 2 (Bloomberg) -- I’m standing atop a defunct bagel factory in the Greenpoint section of Brooklyn looking at what is purported to be the first commercial rooftop farm in the U.S.

“Try this,” says Ben Flanner, handing me a brilliant red nasturtium bloom. “It’s got a nice, citrusy spice taste.”

Indeed it does. Rooftop Farms, tended by Flanner, 28, and Annie Novak, 26, is not only a verdant 6,000-square-foot oasis, it also commands a gorgeous view of the East River and Manhattan skyline.

Flanner left his marketing job at E*Trade Financial Corp. this year to pursue a dream in urban farming, and Novak is a children’s garden coordinator at the New York Botanical Garden in the Bronx. In April, they created Rooftop Farms.

Roof-design company Goode Green calculated the building’s load-bearing capacity, and workers hoisted 100 tons of soil onto the roof by crane. The dirt and installation cost $60,000, put up by the building’s owner, film production facility Broadway Stages. The farmers tilled the soil into 16 beds four feet wide, which are today crammed with dill, heirloom tomatoes, cucumbers, and leafy lettuces.

Very little space is wasted. Hungarian hot peppers are flanked with arugula, a dense “intercropping” not only necessary from a business point of view -- every inch is potential income -- but has environmental utility as well. Pests are less likely to decimate a crop where there’s diversity, and it’s good for the soil to keep varied nutrients in it.

Guinea-Pig Stage

At this scale, individual plants get the farmers’ personal attention. A minor aphid outbreak on the Swiss chard had them spraying their crops, not with pesticides, but with a mild dish- soap solution. Invaders they couldn’t wash away were plucked by hand.

“We’re in the guinea-pig stage,” says Flanner, who hopes to turn this into a sustainable business. The farm is the beneficiary of not only a generous landlord (who doesn’t charge rent) but also a steady supply of free labor in the form of volunteers who find the place on the Internet.

“We don’t have as much in transportation costs, and here in Brooklyn people are willing to spend a little more for good quality produce,” he says.

Marlow & Sons and Anella are among the local restaurants that buy from Rooftop Farms, which also holds a greenmarket outside its front door on Sundays.

“We love that,” says Novak. “Farming is about bounty. It’s a huge joy to be able to spread it around a community that doesn’t have a lot of access to good food.”

Green Payoffs

The rooftop yields more than just tasty greens. There are enormous environmental payoffs as well: Plants absorb rainwater, which would otherwise make its way to the sewer system and eventually the sea, bringing pollutants with it; a layer of soil and vegetation helps insulate the building and reduce energy usage; and locally grown food, which doesn’t travel far, lessens the carbon footprint further. Enough green roofs can even mitigate the “heat island effect” of the urban jungle.

Of course, one roof in all of New York will not do much, but I think these pioneers are on the front end of a phenomenon. Financial incentives and political momentum are already there. New York City building owners can score up to $100,000 in one- year property-tax credits by installing green roofs, thanks to legislation passed in June. More recently, City Council member Bill de Blasio introduced a “food and climate change resolution” to improve access to locally grown food, specifically to reduce the carbon footprint of food production and distribution.

Soil-Free Farm

The Greenpoint farmers won’t be alone for long. Gotham Greens, under construction in Queens, is a hydroponic rooftop farm, which will require no soil at all. Recirculated rainwater, enriched with nutrients, will feed plants via solar-powered pumps. The $1.4 million venture expects to be growing leaf lettuce, herbs and other produce by early next year. Whole Foods Market has already signed on as a customer.

There is certainly expansive opportunity for growth on the New York skyline. According to Columbia University’s Center for Climate Systems Research, “arable” roofscapes make up at least 10 percent of the land area of the city’s five boroughs. That’s over 30 square miles -- or 22 Central Parks -- of potential micro farms.

From this perch in Brooklyn, one sees many roofs, empty and barren, in every direction. Give it a few more summers, and I believe the panorama will be much greener -- and cooler.

(Mike Di Paola writes about preservation and the environment for Bloomberg News. The opinions expressed are his own.)

To contact the writer of this column: Mike Di Paola at mdipaola@nyc.rr.com.

Last Updated: September 2, 2009 00:01 EDT