Farms in cities: Smart ideas for planners

The Shah family that owned The Menengai Oil Refineries, is now doing hydroponic farming in Dubai. They grow lettuce and other greens.

Eight types of urban farms

The eight farm types emerged from the way they use space (planted in soil or on/in buildings), the level of control over growing conditions (like ambient temperature, light, nutrients, water and air flow), and the use of other resources. The latter may be waste sources (such as waste water, bio-matter or waste heat), internet and connectivity networks, and human labour (such as the immediate community). The farm types we identified were as follows:

• Community or allotment farms that are farmed for personal or community use
• Community or commercial soil-based farms that use growing tunnels
• Farms integrated with the built environment, and presenting aesthetic or cultural functions with less focus on produce output (for example demonstration kitchens, or restaurants that promote ethical, sustainable consumption)
• Productive commercial farms that are integrated within the built environment (for example hydroponic farms, greenhouses and rooftop greenhouses) farms that are part of buildings, circulating resources within the building (like integrated rooftop greenhouses)
• Farms integrated into buildings or urban spaces which share resources with a wider neighbourhood
• Indoor farms with artificially controlled conditions (like indoor commercial hydroponic farms)
• Completely automated commercial farms that control the planting process, nutrient management and indoor growing environment.

We observed certain strategies and trends.

Firstly, urban farmers often activate unused spaces. These may be empty lots, leftover spaces next to properties or infrastructure, empty buildings, or rooftops.

Secondly, urban farms ranged widely in size. We documented farms ranging from 3,220 metres square to 4 metres square. Some of the soil-based organic farmers were particular about microclimate (sun, shading, soil quality and water availability).

Some of the more technologically advanced farms were good at manipulating microclimates. They could grow food in seemingly unlikely places, like enclosed storerooms or cupboards.

Thirdly, we documented farms that benefited financially and otherwise from being part of multifunctional spaces. For example, they incorporated restaurants, education programmes, therapy spaces, sport facilities and social gathering spaces.

But we also came across urban farmers who actively discouraged a multifunctional approach. In South Africa, urban farms tended to be isolated - for example on rooftops - and the public were mostly excluded. The main reasons were food safety and the risk of theft or damage. The farmer's main aim was to grow produce to secure an income. Urban farms are often assumed to contribute to public spaces in cities. Some are part of large urban regeneration initiatives. But our findings prove this isn't always the case.

Finally, we saw a range of technological applications and solutions. Many farms used highly sophisticated growing technologies. They include zero-acreage farms, which don't use farmland or open space, but are part of buildings. Hydroponics (growing plants in nutrient-rich water) and vertical agriculture (growing plants on vertical structures) are zero-acreage methods.
But other farms used technology like discarded objects, self-made solutions and organic or recycled materials. This reflects intentions to develop more sustainable farming solutions and save project costs.

Urban agriculture

We noted that low-tech farming technology was highly flexible. High-tech solutions were often inflexible once implemented. For example, one farmer had to completely replace the growing equipment because the technology didn't suit local growing conditions.

Other farmers noted that the integrated nature of the farming systems forced them to grow only a small selection of crops. Urban agriculture can offer cities several benefits. But certain types of urban farming, especially zero acreage farms, can potentially impede sustainable development. They may be more isolated from their surrounding context, less flexible and adaptable, and less multifunctional. Isolation, and only focusing on food production, reduces the economic potential and social impact of these farms.

The choice of urban agriculture technology is an important consideration for urban planners, architects, developers and farmers working in developing cities.