Fig. 1. Example of locally grown produce labels
Photo courtesy of Celina Gómez, University of Florida

Urban agriculture is, according to the United Nations Development Program, “an industry that produces, processes, and markets food, in response to the daily demand of consumers within a town, city, or metropolis, on land or water, dispersed throughout urban and peri-urban areas.”

Urban agriculture gives rise to a new landscape of opportunities for commercial growers. In this seven-part article series, we will discuss the applications of urban agriculture for commercial farmers. We will specifically discuss: Urban agriculture history and production systems; the use of lighting in urban growing environments; vertical farms; rooftop greenhouses and gardens; community gardens; lighting of edibles inside the home; and the economics of urban agriculture.

Historical background

Although hard to visualize, agriculture began with the settlement of human civilization in cities. The transition from nomadic to sedentary lifestyle prompted the development of farming and trading centers in urban areas. Communities worked together and shared insights about techniques to maximize production. Farmers were creative in finding ways to extend the growing season to ensure a constant harvest. Primitive systems that gave rise to the protected agriculture industry were developed, such as fruit walls, which took advantage of sun-heated walls to stimulate fruit ripening during the colder months, or greenhouses, which revolutionized non-native plant production in extreme climates. Urban and cultivated environments coexisted for thousands of years.

The Industrial Revolution brought significant changes to the way food was produced and distributed. Farms had to compete with factories for land and labor. The development of highways and novel transportation systems forced agriculture to rural areas and gave rise to what we know today as “Conventional Agriculture.” Food production was all about mass production, away from the cities, and highly dependent on resource inputs. Food deserts were added to the long list of factors affecting public health and human nutrition. Concerns about food safety related to globalization became a new topic of discussion. Community members were disconnected from their food sources.

Rise of urban farming

Urban agriculture has made a comeback in a concerted effort to address sustainability issues in our food system and promote social and environmental cohesion. The rise of the locavore movement has contributed to changes in consumer attitudes and desires. Consumers today want to support the local economy and are interested in the social and environmental footprint of their food. New generations demand information about where their food comes from. Many regional programs are trying to take advantage of this movement by promoting local food systems. “Fresh from Florida” or “Connecticut Grown” are examples of initiatives to promote fresh agricultural products in participating restaurants and stores. The initiatives not only support local businesses, but also increase familiarity among community members sharing experiences about buying local (Fig. 1).

Residential community gardens, fruit trees in the streets of large cities, restaurant and school kitchens relying on local produce, and commercial “u-pick” farms on the outskirts of a metropolis are all part of urban farming. The increasing interest to promote urban agriculture in or near major metropolitan areas has also motivated the expansion of rooftop greenhouses and warehouse-based plant factories that typically produce high-quality leafy greens to cater niche markets. Hydroponics have also sparked an interest among younger farmers, hobbyists, and home gardeners who aim to produce their own herbs, greens, and low-profile fruiting vegetables. Likewise, young working individuals aspire to benefit from the social, economic, health, and educational benefits associated with urban food crop production. — Celina Gómez

Fig. 2. Vegetable production gardens in urban areas
Photo courtesy of Neil Mattson, Cornell University

Urban farming systems

The scale of urban farms can be small (e.g. green roofs, walls, backyards, or in-home production), medium (e.g. community gardens/farms or individual polyculture gardens/farms, such as in Fig. 2), or large (e.g. commercial scale farms). The size of the operation depends on the budget, production goals, market options, vision and culture of the business, among others.

Small-and medium-sized urban farms have the potential to grow crops for highly specialized markets. Growers can produce a variety of high-value crops like edible flowers or high-end spices. Saffron production in high-tunnels in Vermont is an example of a high-value crop estimated to yield $100,000 per acre, a much higher revenue compared with tomatoes. This type of production is appropriate for the small to medium-scale farmer because it requires attention to detail and delicate handling, has a relatively small market share compared with other vegetables, and can result in high revenue within a small production area. Moreover, it lends itself to urban environments with diverse populations and high median household incomes. An even more specialized small urban farming system is that of the micro-urban farmer, characterized by home gardeners who fully or partially grow their own food in open-spaces or indoors.

Fig. 3A and Fig. 3B. Greenhouse production on the rooftop a supermarket in New York City
Photo courtesy of Stephanie Burnett, University of Maine ; photo courtesy of Celina Gómez, University of Florida

Small and medium-scale urban farms can diversify to supply the various daily needs of local consumers. For example, The Ohio State University developed a Modular Ecological Design, which consisted in an intensive polyculture system for urban areas with the potential to provide a revenue of up to $10 per linear foot. The model consisted in planting short and long-term crops, inexpensive vegetables, and expensive fruit. Similar models have been implemented by many farmers who sell directly to restaurants, CSAs or farmers markets. The polyculture production systems are a consumer-centered approach where, in many cases, individual crops may not result in profit, but the overall production system is profitable. This system has a prolonged production season which favors employee retention and market supply. Small and medium-scale urban agriculture takes place both in the field and under protected agriculture systems.

Urban agriculture at a large scale is only feasible using controlled environment agriculture (CEA) systems. Land availability is a major challenge for urban agriculture. Cities or neighborhoods with enough land may not have the market for CEA-grown crops. In contrast, regions with high-end consumers might not have land that is available or zoned for farming. CEA includes conventional or rooftop greenhouses (Fig. 3) and the up-and-coming plant factories for vertical farming (Fig. 4), which are the epitome of space maximization (number of plants per square foot).

A major motivation for urban agriculture is the integration and recycling of resources in cities and agriculture. Two examples for efficient resource recycling are the use of wastewater for plant production, and the capitalization of excess greenhouse energy to heat buildings. CEA increases the potential of urban farming to a high throughput production system where yields per square foot are maximized and production quality and quantity is sustained year-round. Advances in light, energy conservation, water treatment, and humidity control technologies have increased the adoption of CEA in the U.S., Europe, and Asia. This is more noticeable in temperate regions.

Fig. 4. Plant factories have the potential to maximize the number of plants per square foot.
Photo courtesy of Neil Mattson, Cornell University

Now that agriculture has returned to its origins, opportunities have arisen for new and established commercial growers. Farmers can join new markets or source plant material to farms and community gardens.

Urban agriculture can be a catalyzer of community-based approaches that aim to integrate nature in the urban landscape with sustainable plant production. There are many opportunities to bring jobs and food back to the cities using highly efficient production systems. — Rosa Raudales

In the coming articles of this series, we will further discuss the production systems and the economics of urban farming. Celina Gómez is an assistant professor at the University of Florida (cgomezv@ufl.edu). Rosa Raudales is an assistant professor at the University of Connecticut (rosa.raudales@uconn.edu). Acknowledgements.This project is supported, in part, by the USDA National Institute of Food and Agriculture, Multistate Research Project NE-1335 Resource Management in Commercial Greenhouse Production.