A multiscalar, interdisciplinary study of the social and ecological dynamics of urban agriculture in Chicago, IL

Although always a part of city life, urban agriculture has recently attracted increased attention from diverse groups in the United States, which promote it as a strategy for stimulating economic development, increasing food security and access, and combatting obesity and diabetes, among other social goals. Sites of urban food production, along with other urban landscapes, are also increasingly expected to provide additional ecosystem services, such as stormwater regulation, habitat provisioning, and biodiversity conservation, historically provided by rural areas. This research project employed a mix of quantitative and qualitative methods from the social and natural sciences to explore the spatial, social, and ecological dynamics of urban agriculture in Chicago, IL. The ultimate goal of the project was to develop a foundational understanding of those dynamics as a basis for expanding food production in the city and enhancing its contribution to urban systems at multiple scales. A first step to developing effective urban agriculture policies and programs at the city, neighborhood, or household level is the accurate mapping of existing sites of food production. Mapping efforts in major U.S. cities have been limited in their focus and methodology. Focusing on public sites of food production, such as community gardens, they have overlooked the actual and potential contribution of private spaces, including home food gardens, to local food systems. In the first phase of the research project, public and private spaces of food production in Chicago were identified and mapped through the manual analysis of high-resolution aerial images in Google Earth in conjunction with the use of ArcGIS. The resulting spatial dataset of 4,648 food production sites demonstrated that urban agriculture is an extensive land use type with wide variations in the distribution of sites across the city. Only 16 percent of sites reported to be community gardening projects by nongovernment organizations and government agencies were determined, through image analysis, to be sites of food production. The production area of home gardens identified by the study exceeded by almost three-fold that of community gardens. Study results suggest opportunities may exist for scaling up existing production networks—including home food gardens—and enhancing community food sovereignty by leveraging local knowledges of urban agriculture. Results from the mapping study inspired the second phase of the project, which focused on on-lot and vacant lot home food gardens. The contributions of these gardens to urban systems in the Global North have been overlooked and understudied, even though their production area may, in the aggregate, far exceed that of other forms of urban agriculture. To begin to address this gap, a mixed methods study of African American, Chinese-origin, and Mexican-origin households with home gardens on Chicago’s south side was conducted. (For purposes of this study, a home food garden was defined as a fruit and/or vegetable garden on leased, owned, or borrowed land directly adjacent to the gardener’s residence; it may include plantings in containers or on rooftops.) Study methods included in-depth interviews with gardeners and other household members, participant observation, ethnobotanical surveys and garden mapping, and analysis of the chemical and physical properties of garden soils. In 2012, a total of 31 gardeners were surveyed; in 2014, an additional 38 gardeners were interviewed. Study findings indicate home gardening has an array of beneficial effects, contributing to household food budgets and community food systems, community development, the reproduction of cultural identity, and urban biodiversity. The majority of informants in the study were internal or international migrants. For these individuals, gardening, culture-specific food plant assemblages, and the foodways they supported represented a continuation of cultural practices and traditional agroecological knowledges associated with their place of origin. The gardens of some migrant households also harbored urban agrobiodiversity with roots in the Global South. At the same time, gardens may have less salubrious effects on urban systems and populations. A lack of knowledge of safe gardening practices may expose vulnerable populations to environmental hazards such as soil contaminants. Gardeners reported using synthetic chemical fertilizers and pesticides, sometimes indiscriminately. The repeated application of fertilizers and compost may contribute to the nutrient loading of urban stormwater runoff. These effects may be moderated by the relatively low bulk density and high porosity of garden soils due to tillage and the application of organic matter, which can be expected to enhance stormwater infiltration. While in the aggregate the plant richness of gardens in the study was equal to or exceeded that of a reference ecosystem, only a small percentage of the plant species were native to the Chicago region. Home food gardens also had a unique vegetative structure representing a trade-off between food production and structural complexity. They lacked shade trees and a well-developed shrub layer, and Chinese-origin gardens also lacked perennial groundlayer vegetation. The lack of native plant species and vegetative structural complexity in these gardens may limit their contribution to biodiversity at higher tropic levels. Overall, study results suggest that while the home food garden’s potential contributions to urban systems are significant, outreach—particularly to historically underserved minority populations—and additional research of a participatory nature are needed to help gardeners grow food safely and sustainably in ways that contribute to overall ecosystem health