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The Urban Revolution

How farming in the city may be our greenest option

Farm\’farm\, noun, 4. a tract of land devoted to agricultural purposes.

    When we parse Webster’s definition of a farm, we must ask how big is a “tract,” and what do we mean by “land”? Why ask these questions? If Google Earth was ultra high in resolution, and the target was the southeast corner of Clark and Illinois in Chicago, we would see the rooftop farm of Rick Bayless. Here, during the summer months, the internationally known chef of Frontera Grill and Topolobompo grows some of the key ingredients he uses to work his magic in the kitchen. Bayless’ “farm” is very small, and his land is a tiny amount of dirt in a series of metal bins.
   Is this “farm” meaningful? It is if we recall that as the crushing occupation of Paris wore on during World War II, the French resorted to extremes to maintain their diet. They traveled to the countryside and imported produce in the trunks of their cars to the city. They also farmed undeveloped areas of Ile-de-France and planted their gardens with vegetables. While it’s impossible to definitively prove, urban farming almost certainly contributed to their survival.
   And this was not an exception. In the United States and the United Kingdom,  allotment gardens and victory gardens were a significant source of food (by some accounts up to 40 percent of the produce grown during the height of the war). When facing an unacceptable future, people innovate.
   Fast forward to our times. Many cities have now enacted zoning and building codes requiring the use of green technologies. In Chicago, to be approved for a Planned Development, an entitlement process required for many projects including most tall buildings, a developer must cover 50 percent of a building’s roof with vegetation.
   These green roof requirements are based on three rationales. First, green roofs reduce heat pollution in our cities by eliminating the use of heat-absorbing black roofing surfaces. Second, they promote evaporative cooling during the summer months, limiting the heat load on the building. Finally, green roofs promote infiltration, reducing storm water run-off, which greatly alleviates the charge to Chicago’s sewer system. And what if green roofs become urban farms, if Paris in 1943 becomes Chicago in 2010?
   The answer to this question goes well beyond Rick Bayless’ rooftop garden and raises significant cultural questions.
   On the most basic level, every green roof and every backyard garden offers an opportunity for farming. In Chicago alone, there are an estimated 70,000 vacant lots available for growing fruits and vegetables, herbs and spices. In addition, the existing building stock provides additional rooftop area for farming on a small scale. This can be significant, as highlighted by Rick Bayless and his satisfied clientele.
   But the concept of the urban farm can go much farther. How can Chicago’s urban infrastructure benefit from urban farming? The answers are many. Buildings are an effective means for rainwater harvesting, and using this water domestically or for irrigation eliminates the need to deplete our aquifers. Also, glass can increase the heat load on a building’s air conditioning system, but greenhouses, or indoor farms, are more productive than outdoor farms by a ratio of five to one. What looks like an energy issue at first could lead to a significant byproduct. Greenhouses also provide opportunities to decrease the use of pesticides and other harmful chemicals. The local production of food also lowers transportation and storage costs while eliminating carbon emissions from cross-continental transport.
   These are basic byproducts, but the benefits go beyond these direct impacts. The fact is that there are a range of consequential issues that make the urban farm truly significant as a green technology. Presently Chicago’s urban waste system does not encourage composting, but composting produces soil, limits the waste products delivered to land- fills and has the potential to also produce energy. Organic waste “produced” in great quantities by our buildings could be used to sustain food crops grown on them (For a significant reading on these issues, look at the Vertical Farm Project by Dickson Despommier, Mailman School of Public Health, Columbia University, www.verticalfarm.com).
   Finally, there are truly radical changes to our buildings that we have not considered. What if we found cattle grazing on the roof of the United Terminal at O’Hare? Ideas like this one might sound farfetched, but ought to be considered.
   In our design of buildings and cities, we are at an Obama moment—a point in time where people are open to new ideas and directions. On some scale, urban farming is a practical alternative to large and remote agribusinesses. All we need to do is say “yes we can.”

Published: April 04, 2009
Issue: 2009 Spring Green Issue