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
If Gotham's approach lacks the rural romance of dirt farming, there's no arguing with its results. In its first year of operation, Puri says, the facility grew 120,000 pounds of produce—three times more than the Grange, in about a third of the space. That's partly because during the winter, while the Grange lies fallow, Gotham keeps growing, aided by high-pressure sodium lights and a 55-kilowatt solar array that creates half the power the greenhouse needs throughout the year.
Puri guides me toward a bank of butter lettuce, packed as densely as subway passengers but healthier-looking. He extracts a head. It trails a beard of tangled and ghostly white roots, which grow smaller than they would in soil because the plant needn't strain for its dinner.
He pulls off a leaf. It's one of the most tender bits of lettuce I've ever tasted.
"It's not dealing with rain, it's not dealing with hail, it's not dealing with wind, it's not dealing with huge temperature swings," Puri says. And unless the growers alter its powdered rations, Gotham's butter lettuce will taste exactly the same year after year.
That head of lettuce sells for $3.99 at Whole Foods in Union Square. Gotham is focusing on supermarkets, where volume and consistency are required. Puri says the company expects to close the deal soon on two new rooftop facilities in New York of 50,000 to 60,000 square feet each, one likely for greens and the other for vine crops. BrightFarms, another hydroponic company based in Manhattan, is breaking ground on a monster 100,000-square-foot urban greenhouse nearby and has contracts with supermarkets in Oklahoma, Pennsylvania, and elsewhere that will be supplied from local greenhouses, guaranteeing freshness and eliminating transportation costs.
The next step in the evolution of urban agriculture may be vertical farms, multistory greenhouses illuminated by a combination of sunshine and artificial light. If built on a sufficient scale, they could make a sizable contribution to the world's food supply. Stackable farms are already up and running in Korea, Japan, Singapore, and Chicago.
One threat to the uniformity of hydroponics is that disease in one plant can quickly infect an entire crop. To avoid spreading pathogens, says Dickson Despommier, a vertical farming specialist and a professor at Columbia University, workers might be required to shower and don sterile uniforms before reporting to the grow room.
Gotham Greens' single-story facility isn't that rigorous—it has roughly the same sanitary standards as a commercial kitchen—but it does strictly limit its visitors. A hydroponic farm can grow lots of produce, but it will never be a place where just anyone can lend a hand.
Which model will prevail, Gotham or Grange? I can't help thinking that Gotham has the upper hand. It's easy to imagine enormously productive, industrial-scale greenhouses multiplying across America's roofscapes like so many Walmarts, feeding far more people than the quirky, community-friendly farm over at the Grange ever will.
But I hope that every city gets the chance for a Grange or two, where fairytale eggplants take root above the mad traffic, and the office drones know that rows of sunflowers nod just overhead.
David Ferris writes Sierra's "Innovate" column and lives in Washington, D.C., where he grows his greens at street level.
This article was funded by the Sierra Club's Climate Recovery Partnership.
This story has been corrected.
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