04.11.07
Stop Your Gardens – We’re Saved
Well, maybe don’t stop teaching your kids to garden but there is a lot of interest in saving the planet’s food production by moving it indoors.
The world food supply is vulnerable to climate shifts, the globalization of pestilence and blight, and improvements in crop resistances that can lead to pollinator failures (bees getting mites) or increased allergies. Worse, land for cultivation is shrinking and the population is growing. As a final kick we’re moving food around the globe at an environmental cost that may aggravate all the other downsides.
Green houses and hydroponics farms have been around for hundreds of years but the next generation envisions farming in skyscrapers. The New York Magazine’s recent article on the development of these vertical farms presents the hope to put 30 acres in a place like New York City on one acre of land.
Could this solve a potential food crisis or will it just bring designer food to Manhattan?
Unseasonable freezes and droughts would no longer be a concern. Violent natural events might take down a building or even a region but if most of the world’s supply is stable we should be able to cope with some outages.
Flavor may return to mass-produced food if there is a reduced need to make food transportable for long distances. Blight or pest resistant strains are less necessary if you can stop the problem at the door to the farm.
My daughter hates tomatoes – unless they are the fabulously expensive heirloom varieties. Trying to explain the tradeoff between taste and the need to get more calories to market in a crowded world isn’t always easy. It gets even worse when you try to talk about the need for resistant crops to save more of the world’s starving people but risk that you might kill off needed ecosystems along the way.
But modern farms are thousands of acres. We’re not talking about backyard or roof top gardens that are fairly cheap to start. What kind of dent can a 30-acre farm that might cost millions, make in the food supply?
Serious garden yields aren’t so easy to come by on the net. Some of the most interesting articles carry dates in the 1940s. Assuming the skyscraper uses hydroponics, a thirty story building about the size of a football field or 1 ½ large city blocks ( 1 acre) could keep 1,500 people fed for a year on soybeans or 1,100 people fed for a year on tomatoes. (These numbers are very approximate, based on lab hydroponics yields and one level of plants per story.)
 There is some indication that Eurofresh Farms, the largest hydroponics grower in the world, has much, much better yields (they could feed over 400,000 people a year on their tomatos if the recipients didn’t smash the green houses because they were sick of tomatoes) but their greenhouses are high-tech conventional flat greenhouses that use the sun. The extra hardware needed to light the building may cut yields and 100 years of exerience may pay mega-dividends over a blab-technician’s experience.
 Vertical Farms thinks they might be able to set up a full farm complex capable of feeding 50,000 people a variety of foods, including eggs, in 18-49 stories. I’m not sure that chickens need to be running around  an urban, indoor farm (even if caged) or that they really would want to process the city’s wastewater in the food building. Eliminating both design constraints should make it even more efficient.
