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Coming soon: commercial scale rooftop produce

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Canadian entrepreneurs have designed and operated a greenhouse so energy efficient that it can function at commercial scale in chilly Montreal and still break even. More will come in Boston and New York.

Lufa Farms has broken even on its operations in chilly Montreal, over 50 degrees of latitude north of the Equator.

The next time you're in Montreal or New York, the lettuce in your Caesar salad might come from the building across the way. Demand for locally grown produce is rising in urban areas, and at least some commercial farming will happen on rooftops.

There was a time when New Jersey fed the Big Apple; produce was consumed locally before advances in refrigeration and transportation transformed agriculture into a global business. Your supermarket's produce might have been shipped from half a world away.

Rising energy costs and concerns about food security have led some Canadian entrepreneurs to reconsider and reimagine local farms. Farmland has long since been paved over, but there's plenty of space for rooftop greenhouses.

Lufa Farms is on the verge of an urban greenhouse-building spree. It proved its concept in Montreal, breaking even on operations earlier this year, and is negotiating Series A financing to build at least four more multi-crop facilities in Canada and the U.S.

Being successful in cold Montreal, the "most hostile" environment for a greenhouse, proves that the model will be sustainable closer to the equator, said co-founder Kurt Lynn. The tricky part is turning a profit by scaling a "farm" to the right size and carefully managing energy efficiency.

In an interview today, Lynn described how Lufa Farms devised a system of insulted "curtains" to shield sensitive crops from direct sunlight and keep the harvest safe during Canada's frigid winter nights. Select supplemental lighting also helps control energy costs.

High efficiency natural gas boilers produce nearly net zero carbon dioxide; the plants absorb the gas during photosynthesis. Biomass will be utilized in the future, Lynn noted.

The underlying building receives the added benefit of a 20 percent energy cost reduction, Lynn said. "We provide a huge insulator to the building below." Greenhouses also take advantage of heat escaping through the rooftop.

Additional greenhouses will soon be under construction in Montreal with a potential site having been chosen in New York City. The Bronx and Brooklyn are the most favorable boroughs, Lynn noted. Boston is also under consideration.

Lufa farms competitor Brooklyn Grange has already constructed the largest rooftop farm in the United States on an old Navy warehouse in Brooklyn. BrightFarms is planning another that would yield one million pounds of hydroponically-grown produce annually, including herbs, lettuces, and tomatoes.

"We look at food creation in the same way as you look at making subway stops," said Lynn. "We're considering high density residencies such as senior's home; there's going to be a boom in the future, and [farming] is good occupational therapy.

(Image credits: Lufa Farms)

Tomato plants grow over 20' high within the greenhouse(s). "It's like a jungle in there," Lynn said.

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David Worthington

Contributing Editor

David Worthington has written for BetaNews, eWeek, PC World, Technologizer and ZDNet. Formerly, he was a senior editor at SD Times. He holds a business degree from Temple University. He is based in New York. Follow him on Twitter. Disclosure