01 July 2008
Vertical Farms Grow Food by Growing Up, Not Out
Researchers see potential to help solve food shortages
Washington -- People in urban areas in the future may be able to buy their food from a truly local source -- a farmer who has raised crops and small livestock in or on top of the buildings where they live or work.
Columbia University professor Dickson Despommier is one person who believes the concept can become a reality.
Despommier, an environmental health expert, says that if all farmers continue to use current land-intensive agriculture practices, they will not be able to produce enough food to feed the world's population, which will increase by an estimated 3 billion people by 2050. By that time, 80 percent of the world's inhabitants will live in or close to cities, according to verticalfarm.com, which grew out of a student project Despommier initiated in 2000.
A new model of farming is needed, Despommier said. That is, farming "up, not out," because nearly 85 percent of the world's arable land already is in use. More land still could be lost to erosion, other experts say.
The idea is "vertical farming" -- using the space of tall buildings to grow food year-round in environments cooled and heated by energy produced by rooftop solar panels.
The idea depends upon use of existing greenhouse hydroponic technologies, which grow plants using mineral nutrient solutions in an inert medium such as gravel. Researchers see this as a way to grow pesticide-free food while saving limited and costly energy and water resources. The controlled environments would prevent the airborne spread of pests and diseases, Despommier said.
Greenhouses can grow any crop anywhere, said Gene Giacomelli, director of the Controlled Environment Agriculture Program at the University of Arizona.
He told America.gov that with greenhouses, "we can adjust the plant environment to the conditions of the site to produce a crop." That means adjusting for such variables as air temperature, day length and sun intensity.
Despommier argues that the price of weather- and pest-related crop failure is growing ever steeper as the global population mushrooms. "The world is running out of resources faster than what it can replace,” he said. In addition, he said, "the climate is changing more rapidly than we can adjust to."
Other proponents of indoor farming say it would eliminate environmentally damaging runoff because nitrogen and other nutrients would be filtered out of animal waste and used as fertilizer.
Vertical farms also would allow cities to grow enough food to replace lost productivity as farmland is urbanized, some supporters say.
Despommier says some world cities -- Inchon, South Korea; Abu Dhabi, United Arab Emirates; and Dongtan, China -- already plan to incorporate vertical farm buildings into their schemes to become environmentally sustainable population centers and that several companies are interested in helping.
He said vertical farms also could be a boost to developing countries that have ample sun, but limited water, and could give worn-out soils a rest.
Despommier estimates that a 30-story building taking up one city block could feed 50,000 people with vegetables, fruit, eggs and chicken. Upper floors would grow crops; lower floors would house chickens and fish ponds. Hydroponics would be used.
The main obstacle is finding money for more research and development, the researcher said.
Other proponents say a more ambitious approach would be to design office buildings with double glass facades that would allow winter sun in, while insulating against noise and heat loss.
As oil prices rise, the efficient use of resources in greenhouses looks more attractive, Giacomelli said. Cheap food is based on cheap energy for transportation, on nitrogen-based fertilizer and on cheap water, he added.
Giacomelli said greenhouses in America are already producing tomatoes for fresh consumption and have the potential to grow even more high-value vegetables. Up to 50 percent of the fresh tomatoes Americans buy in winter months, he said, are grown in greenhouses.
He said greenhouses will gradually begin to increase in the United States as they have in Europe and that several large agricultural companies with operations in California, Nevada, Florida, Arizona, Texas and northern New York have invested in them.
The idea of indoor farming isn't without controversy. Some say getting adaptable sowing and harvesting equipment into buildings would be difficult. Others cite the labor-intensity of this form of farming.
Despommier said his interest in vertical farming began with his interest in preventing disease transmission among humans. But now he says he also is excited about the potential to help solve impending food shortages.
"We want to help feed the country and the world with controlled-environment crops," Giacomelli said.
