sierraclub.org - sierra magazine - nov/dec 2012 - up on the farm
Two models for rooftop agriculture vie to feed the Big Apple
Text by David Ferris | Photography by JJ Sulin
Flanner, 31, quit his job at E-Trade three years ago because he wanted to try his hand at farming. Still, he didn't want to give up his cosmopolitan lifestyle. He hands me a bag of mixed greens and waits expectantly for my judgment. They are fresh and tangy, the result of a special lightweight soil called Rooflite, made from mushroom compost and mineral aggregates, that's been dressed with the farm's own compost.
"Our leaves change with the weather, the compost, and the nature of the soil, which creates surprises. That's all really exciting for the chefs and the people who appreciate our produce," Flanner says. Among that number is Lois Burnett, general manager of MoMo Sushi Shack, who garnishes dishes with the Grange's microgreens. "The experience has been fabulous," she says. "The produce is really fresh, and we definitely like to talk about it [to our customers]."
A recent survey by Columbia University determined that 3,079 acres of public and private buildings in New York have rooftops that are big and flat enough to support urban agriculture. Most of these are in the Bronx, Brooklyn, and Queens. (Supplying all of New York's temperate fruits and vegetables would require 232,000 acres—an area larger than the city itself.) Onions, beans, and grains are poorly suited to urban growing, but rooftop farms could contribute a modest portion of New York's leafy greens, herbs, and vine crops like tomatoes and cucumbers.
Unless, of course, someone figured out how to grow a whole lot more food in the middle of the city in some other way.
Flanner knows where my next stop is. "Don't count dirt out," he pleads. "There's a lot to be said for dirt."
The next day is even more sweltering, and I arrive at Gotham Greens in the hottest part of the afternoon. This farm is in a desolate industrial stretch of Brooklyn near a wastewater-treatment plant. Unlike the Grange, it can be seen from the street—a greenhouse peeping over the roofline.
I walk up three flights of stairs and directly into a transparent 15,000-square-foot structure that is crowded with lush lettuce, cilantro, and parsley. No one is there. My sweat glands were bracing for the greenhouse effect, but somehow it seems a few degrees cooler than outside.
I yell hello and roust Viraj Puri, Gotham's 31-year-old CEO, who is there by himself after sending his 20 workers home because of the heat wave.
In contrast to my visit to the Grange, this interview is all efficiency. There are no interruptions. Puri explains how sensors located all over the greenhouse track temperature, humidity, carbon dioxide, oxygen, and light levels. "All that information is fed back to a computer-controlled system, which is programmed to turn on and off to achieve the climate conditions that we desire."
There is a slight breeze created by two fans whirring overhead and vents in the ceiling and the walls, which the computer has wisely chosen to open. A layer of fabric has been drawn like a curtain over the ceiling to filter the sunlight. The Gotham model is all about control—over the building, crops, and visitors.
Puri has brown eyes and a square jaw, and his white button-down shirt shows not a speck of dirt. The entire facility, in fact, is spotlessly clean and meticulously organized, which perhaps is not surprising for an enterprise looking to create prodigious amounts of food without using soil.
The key is hydroponics. Along one wall are propagation trays, where buds of basil sprout from minuscule cubes of rockwool, a material made from superheated basalt. After a few days, the shoots are transferred to long white plastic trays, where they are fed by a stream of constantly recirculated water mixed with powdered nutrients like nitrogen, phosphorous, and potassium.
"Crops don't technically need soil to grow," Puri explains. "What they need is oxygen, CO2, sunlight, water, and nutrients, and we're able to provide it all right here to ensure really consistent yield, very healthy crops. And we don't contend with many of the issues that conventional farms face."
The greenhouse is as peaceful as a meditation center, attended by the faint sound of splashing water. The trays are perfectly aligned, and black tubes feed them at nearly identical vectors. Jenn Nelkin, the head grower, is a hydroponics expert who once grew cucumbers and bell peppers at the McMurdo research station in Antarctica.
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