One of the most e-mailed articles on the New York Times website today is Dickson D. Despommier’s op-ed “A Farm on Every Floor.” He has an intriguing proposal: grow crops inside tall buildings, a practice known as vertical farming. Since climate disruption is altering rainfall patterns and causing more floods and droughts, farmers are finding it harder and harder to produce food for a growing population. And agriculture as practiced today is a major user of water, which is in short supply in regions throughout the world. 

Despommier has started a business to build vertical farms, so you can take his rosy picture with a grain of salt. But it sounds pretty appealing:

Imagine a farm right in the middle of a major city. Food production would take advantage of hydroponic and aeroponic technologies. Both methods are soil-free. Hydroponics allows us to grow plants in a water-and-nutrient solution, while aeroponics grows them in a nutrient-laden mist. These methods use far less water than conventional cultivation techniques, in some cases as much as 90 percent less. …

A vertical farm would behave like a functional ecosystem, in which waste was recycled and the water used in hydroponics and aeroponics was recaptured by dehumidification and used over and over again. The technologies needed to create a vertical farm are currently being used in controlled-environment agriculture facilities but have not been integrated into a seamless source of food production in urban high-rise buildings. …

Vertical farms would produce crops year-round that contain no agro-chemicals. …Vertical farming could finally put an end to agricultural runoff, a major source of water pollution. … New employment opportunities for vertical farm managers and workers would abound, and abandoned city properties would become productive once again.

Since cities are attracting a growing share of the world’s population, it makes sense to produce food in urban areas and cut down on transportation costs. And, as Despommier points out, easier access to fruits and vegetables can help combat health problems like obesity and diabetes.

For vertical farming to take off, someone needs to build a facility to show that it works. Despommier gives a suggestion:

I estimate that constructing a five-story farm, taking up one-eighth of a square city block, would cost $20 million to $30 million. Part of the financing should come from the city government, as a vertical farm would go a long way toward achieving Mayor Michael Bloomberg’s goal of a green New York City by 2030. Manhattan Borough President Scott Stringer has already expressed interest in having a vertical farm in the city. City officials should be interested. If a farm is located where the public can easily visit it, the iconic building could generate significant tourist dollars, on top of revenue from the sales of its produce.

But most of the financing should come from private sources, including groups controlling venture-capital funds. The real money would flow once entrepreneurs and clean-tech investors realize how much profit there is to be made in urban farming. Imagine a farm in which crop production is not limited by seasons or adverse weather events. Sales could be made in advance because crop-production levels could be guaranteed, thanks to the predictable nature of indoor agriculture. An actual indoor farm developed at Cornell University growing hydroponic lettuce was able to produce as many as 68 heads per square foot per year. At a retail price in New York of up to $2.50 a head for hydroponic lettuce, you can easily do the math and project profitability for other similar crops.

 
It sounds like a great idea, and certainly worth pilot testing. Can it really work out as Despommier promises? Large agricultural producers would be smart to invest in the idea, but the producers of pesticides won’t be happy unless their products can play a lucrative role. But if there’s a profit to be made in doing something that happens to be sustainable, it might work out.
 

P.S. In a similar vein, the idea of urban fish farming is also intriguing – see articles from the New York Times and Seed Magazine about a biology professor who’s raising tilapia in Brooklyn.