Articles
Making Urban Farming Scalable With Fish
Why aquaponics may be the future of urban farming, and one solution to our local food problem. The majority of Americans live in urban environs....
01.14.10
\n
Cityscape hopes to launch its first farm in the first half of 2010. Their aquaponic greenhouses would be built in vacant lots and on rooftops. To start out, they are considering sites in San Francisco's sunnier southern and eastern zones to capture plentiful solar energy. To monetize, Cityscape will serve as a wholesaler to local distributors and restaurants as well as operate a weekly farmers market. Yohay says there is interest from Bay Area restaurants enthusiastic about hyper-local and organic produce like strawberries and tomatoes being produced even in the off-season. That's another advantage of hydroponic farming: the changing temperatures and seasons do not limit the indoor growing cycles.And, for Yohay, the longer growing season is just one of many advantages. Aquaponics could also provide a more efficient use of our water resources. According to UNESCO, 70 percent of our fresh water worldwide is currently being used in agriculture. Fresh water in normal agricultural usage quickly becomes contaminated with petro-industrial chemicals and fertilizers. Aquaponics, on the other hand, constantly recycles the same organically fertilized water. "The embedded water and the embedded energy will be less in our model than in traditional models. We plan to initially power these aquaponic greenhouses on the grid and then switch to solar and other sustainable energy sources."By eliminating the need for soil and using fish waste to feed the plants, aquaponic farming also eliminates the need for chemical fertilizers. Because the system takes nutrients from the fish instead of oil-based fertilizers, it relies on a mere fraction of the inputs and outputs compared to conventional field agriculture.So could this sort of farming actually work on a national level? Dr. Dickson Despommier, the Columbia professor and vertical farming guru, thinks so. He cites Cityscape's "light weight and highly productive" structure and the speed with which food production can begin as two key indicators of potential success. One reason for this quick growth cycle involves the relationship between a plant's environment and its energy resources. A plant traditionally expels a lot of energy sending down roots to look for water and nutrients. In an aquaponic setup,those needs are already met, which produces a shallower root systems and allows the plant to expend more energy on leafy, vertical, vegetative growth. Yohay predicts that "at Cityscape we will produce just over one hundred tons of food in twenty thousand square feet of space per year-the first year will be less as we wait for the fish to cycle up, but after that we'll operate at regular production levels."A national network of urban farms is also something that Yohay envisions. "If we are going to make substantive change in our industrial model we need to look at big solutions, that means looking at the parts of the country that need this the most. We've been invited by cities like New York, L.A., Chicago, and even as far as the Virgin Islands. Our [model] is a completely site independent methodology-we aren't reliant on soil testing and the perfect parcel of land; we don't even need land. The soil in cities is often times ill-suited for agriculture because of heavy metals; we mitigate these dangers by avoiding the use of soil all together. The fact is the world is running out of quality water and soil. Look at the food riots in Asia, Latin America, and Africa. These food shortages were partially the result of the diminishing quantity and quality of soil."As in any healthy natural system, diversity is key. Aquaponic and hydroponic farms are but one of many potential urban farming solutions. Yohay concurs, "if we deconstruct the industrial model of a centralized Big Ag monopoly then we need in its place a diversity of offerings. Cityscape is not the entire solution, but we are a part of that solution. I don't consider other urban farmers as competitors. We need each other if we are gong to be competitive on a national scale. We need the money and political will that comes from having a critical mass of people and organizations growing their food responsibly in cities. Our real competitors are the Big Ag companies hiding the externalities, both environmental and social, of growing their food in irresponsible ways that pollute and destroy our land while exploiting unfair labor practices."Oil-drenched food inefficiently transported and treated with chemicals. That doesn't sound too appetizing. Organic tomatoes and strawberries growing harmoniously with fish. That just might be deliciously scalable.Guest blogger Adam Starr is a freelance writer. He lives in San Francisco.