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11 clean tech innovations that can change the world

By: Bryan Nelson on April 5, 2010, 10:23 a.m.
Clean tech innovations: Hydroponic crops stacked in greenhouse

Photo: Valcenteu/Wiki Commons

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Vertical farming

As we pave over farmland and use it for other purposes, farmers today must produce more food with less land. The answer to the problem, according to a company called Valcent, is to build our croplands like skyscrapers: straight up. Valcent has pioneered a hydroponic farming system that grows plants in rotating rows, one on top of another. Not only does the rotation allow for the precise amount of light to hit each of the plants, it also uses far less water than conventional farming methods.