High-Rise Farms: The Future of Food?

That's the hope of scientists and architects who are erecting a unique
strategy to feed a swelling population on a planet with finite
farmland. "In another 40 years, there'll be another three billion
people. That's the problem," said Dickson Despommier, a professor of
public health at Columbia University in New York. One solution,
Despommier believes, is to grow everything from salad greens to staple
grains year-round in high-rise buildings at the hearts of urban
centers. This so-called vertical farming could put food within easy
reach for billions of people while reducing carbon emissions from
shipping crops across continents and oceans, he notes. "[The concept]
is based on technologies already in use throughout the world, mainly
high-tech greenhouses," Despommier said. For example, many existing
greenhouses use hydroponics, a technique for growing crops in smaller
spaces using nutrient-enriched water instead of soil. But for now
high-rise farming remains just an idea. One challenge is how to stack
the greenhouses so that layers of crops get enough light to be grown
in a vertical structure, Despommier notes.

http://news.nationalgeographic.com/news/2009/06/090630-farm-towers-locally-grown.html