Expanding communities have absorbed more and more "cornfields" at the edge of town for development. Now, an idea germinating for many years is rapidly taking root in North American cities. Communities are reclaiming urban property and returning them to "cornfields." Urban farming is growing in many communities. This is especially true in older urban cities with large tracts of brownfields and underutilized property available for re-development.

The genesis of the trend is centered on the idea of sustainable communities, carbon footprint reduction, and meeting urban needs (e.g., overcoming areas of communities where fresh local produce has not been available) The re-development is not without real issues, but there are also real benefits and solutions.

Significant Initiatives
Greensgrow (www.greensgrow.org) started in 1998 as a one-acre plot on the site of a former steel-galvanizing factory in downtown Philadelphia. Vegetable plants are grown in raised beds or hydroponically (i.e., in water beds). The Philadelphia Project, according to Urban Gardening Help, (www.urbangardeninghelp.com) now consists of a 6,000-square foot greenhouse, a 1,500- square foot nursery, and a 4,000-square foot hydroponics system. The project will be expanding to include the addition of a 6,000-square foot lot adjacent to the main farm that will become a vermiculture project. Greensgrow provides food to local residents, and also serves as an education center and a clearinghouse for urban agriculture issues.

Detroit is also getting in the farming business. One of the more aggressive urban farming initiatives was reported in a January Chicago Tribune report (www.chicagotrib.com/business), which highlighted the development of an initial 30 acres and $30 million investment in an urban farming program. The Hantz initiative is the first step in a goal of farming over 5,000 acres of land in Detroit. Within the Detroit city limits of 139 square miles there are many acres available for redevelopment. The Hantz initiative may include tree groves were the soil is too contaminated to support vegetables; empty factories may be converted to hydroponic beds for specialty vegetables, fruit, and herbs; mushrooms may be grown in dark basements.

Whatever develops at the Hantz project, Mayor Dave Bing was quoted in the Tribune article: "Urban farming will be part of Detroit's long-term redevelopment plan," but noted that "... preparing land for widespread agricultural purposes is a process that cannot occur overnight." Concerns range from wondering who would pay for cleaning pollutants out of the soil and removing utility infrastructure, such as gas and sewer lines, to figuring out how to rewrite the city's zoning laws and adjust property tax rates and property values to allow for commercial farming. The potential for jobs, however, is encouraging and may be a driver to resolve the other issues.

A good example of innovative urban gardening is the Edible Schoolyard project in New Orleans (www.esynola.org.), which was modeled after the Alice Waters original in Berkeley Calif. The project resulted from the Katrina disaster and excess underutilized land. The Edible Schoolyard project was highlighted at the Brownfields 2009 Conference in New Orleans, where the premier of the video documentary "Nourishing the Kids of Katrina" was presented. The garden serves 320 students from Green Charter School in grades K-8 and 46 students from Arthur Ashe Charter School. Students cultivate, plant, harvest, process, and cook with the produce from the schoolyard garden. The project is a core of their curriculum, not a side activity.

Aggressive, yes, but these kinds of projects are just the tip of the real development needed if urban farming on brownfields is to have an impact on the nation's food supply and the redevelopment of brownfields. These projects impact only a small portion of the potentially available land. Many systemic and technical issues need to be overcome to make urban farming on a large scale a wholesale reality. Key issues include:

• Resolution of farming on land potentially impacted with urban-life chemicals. Vegetables tend to adsorb chemicals from the soil into their roots and into the vegetables themselves. All land is not inherently contaminated by direct prior activities, but in many urban areas the surface of the land may be subject to years of "non-point" source urban impacts. Burning of fossil fuels over many years, historic use of lead-based gasoline, and other urban activities have left a patina of constituents on the ground surface that may impact the quality of produce from urban gardens.
• Rezoning and local ordinances provide major constraints on effective reuse of property. Zoning and tax issues can bring about contentious decisions. Many cities may need to pass ordinances or local laws to allow urban agricultural uses (e.g., bees in the city). Issues can revolve around impact to nearby communities: zoning and tax consequences, traffic and transportation (e.g., tractors and trucks on local roads, road closures), air quality (e.g., odors), and potential environmental impacts (e.g., vectors from composting operations).
• Seasonality limits. Specialty farming (e.g., hydroponics, mushrooms) can be conducted year round. Farming large tracks of open land can only be conducted within the natural local growing season. In the northern rust-belt cities with large tracts of brownfields, the reduced growing season significantly limits and influences the economic business plan for urban farms. Startup costs need to be amortized over a longer period of time. Labor needs to be flexible to the growing season, which may limit the acquisition of year round jobs and influence labor rates.

You can put a working farm on a brownfield, or a developer can construct a multi-use building, like this one in Chicago, in which to perform farming activities on a green roof.

A Long Term Vision
Perhaps the vision of urban farming within the next 10 years could include:

• Urban farms that are a part of the sustainable fabric of developing or re-developed communities, integrated well into the planning, social and economic framework. This vision may comprise urban plots of 300 to 500 acres within communities arranged in a plan similar to urban green spaces and forest preserves. Idled industrial plants and large sections of urban teardowns would be prime targets. Major transportation corridors would be maintained, but roads internal to the plots would be milled and recycled. Some existing utilities would be enhanced to support irrigation and stormwater needs. Others utilities may need to be abandoned.
• The target for the farms would be to be carbon neutral, utilizing alternative power sources and green spaces to offset their carbon footprint. The surface soils would be deeply tilled and regraded to allow for efficient use of farm machinery, to facilitate drainage and on-site stormwater management, and to receive the addition of new soil and soil amendments. Soils would be routinely tested for quality and amended organically as needed. Soils with high levels of unwanted constituents would be treated through phytoremediation. These areas would be planted with trees or special vegetation to selectively uptake the unwanted constituents from the soil, thereby restoring overall health over several years. Rain gardens and treatment wetlands would be utilized for stormwater management.
• Previous industrial buildings would be rehabbed (e.g., cleaned, asbestos and lead based paint removed), fitted with solar voltaic roof panels, or other appropriate alternative energy systems, for light and power. Buildings would be fitted with raised beds, hydroponic beds, or vertical growth trellises for intense farming of high value produce. Dark or windowless spaces could be used for mushrooms. Portions of buildings would be retrofitted for composting with the target of management of all excess green materials being managed on site and converted to natural organic fertilizers. Odors would be managed within the buildings.
• The urban farm would have agreements with the local large food chains to provide specialty produce year round: herbs, lettuces, mushrooms, green and red peppers, specialty cucumbers, and some tomatoes.
• The high costs of setup and farm initiation would be partially offset in the business plan by the large and long-term reduction of transportation costs for produce getting to the users. A focus would be on the business triple bottom line: social and environmental, as well as the economic benefits.
• Communities would develop and streamline zoning, tax revisions, and ordinances needed to facilitate the urban farming business.

Bring on the tractors!

Ken Kastman is a PE and Principal Engineer at URS Corporation, Chicago, IL