How a unique way to green up cities can support communities, help tackle food insecurities, and combat the urban heat island effect.

What are Urban Farms?

Urban Farms are any kind of city space that is used for food production.

They can take the form of:

• Food producing gardens and allotments.
• Small farms with animals and livestock.
• Edible landscaping.
• Vertical farms using techniques like hydroponics.

Beyond food production, urban farms have a range of benefits:

Urban farms can improve mental health, social networks and community

Mental and physical health

Doctors have recently started prescribing courses in gardening or working alongside animals as part of mental and physical health treatment programs.

“Green social prescribing” connects individuals to communities in outdoor environments in a bid to improve mental and physical health holistically.

These schemes provide opportunities for sensory connection with nature. This, in turn, helps to reduce stress and anxiety, enhances cognitive function and improves emotional regulation. Alongside mental health benefits, immersion in nature has been shown to improve sleep and reduce blood pressure, leading to improved health in all areas of life.

Community and connection

Urban farms can promote community and connection. For instance, by allowing community members to work and build projects together they can create a sense of belonging. This can increase community pride and empower marginalised people. Additionally, commercial urban farms create jobs, providing a range of employment opportunities, from marketing and retail workers, to chefs and farmers. 

These spaces can be multifunctional, even venues for events and gatherings. For example events can include weddings, birthdays, and even funerals. They can form a backdrop of community against an urban skyline.

Education

Farms are a great space to educate people about food production, plant life, and animals. They can help people to learn about nutrition, about eating natural and unprocessed foods. As well as give children an opportunity to interact with animals, fostering skills and interests which would be out of reach to many urban children.

Aesthetics

Urban farms can also improve the appearance of built environments. This is often neglected as a superficial or unimportant point, however aesthetics play a huge role in peoples mental health. By creating green space you provide room for peoples nervous systems to relax amongst the hustle and chaos of the city.

Tackling food insecurities

Food insecurity is defined as the consistent lack of food to have a healthy life. In the UK 7.2 million people experience food insecurity every year. By shortening the distance between food production and consumption, urban farms can provide nutritious, unprocessed food to communities that previously lacked access to it.

Producing food in a small footprint and offsetting strain on supply chains

Cities rely on long supply chains for their food. While there isn’t enough land in dense urban areas to sustain whole cities, urban farming can alleviate some strain on supply chains.

Vertical farms were initially conceived as part of a hypothetical self sustaining sky scraper, capable of providing food for its own residents. Because of this they are designed to maximise food production in limited space, with crops stacked vertically in tall columns. With their unique space saving design they are able to produce far more food per square metre than traditional farms.

Hydroponic farms use a water based nutrient solution instead of soil. By using creative irrigation methods, like recycling nutrient solutions, these farms are able to minimise their use of water.

These types of controlled environment farms are also able to reduce their use of chemical fertilisers and pesticides. Growing food in easily monitored conditions allows farmers to integrate beneficial insect populations to control pests and improve crop health. While in hydroponic systems farmers control the nutrients supplied to the plants directly through the solution, bypassing the need for harsh chemical fertilisers.

Environmental benefits of urban farms

Tackling the urban heat island effect

Urban farms can help combat the heat island effect through evapotranspiration as well as providing shade. Cities can benefit from an enhanced micro climate by allocating more land to green projects like urban farms.

Plants release moisture into the air as part of their respiratory process known as evapotranspiration. And this moisture has a cooling effect on the surrounding area.

Replacing exposed concrete surfaces with vegetation reduces urban heat retention, helping to lower temperatures of increasingly warm cities. In addition, vegetation can insulate buildings, keeping them warmer in winter and reducing energy consumption, along with the associated heat emissions.

Supporting biodiversity and improving soil health

Urban farms also improve biodiversity from the ground up. For example, by using sustainable farming methods like crop rotation, mulching, and biochar they can help to tackle soil degradation.

Healthy soil supports micro organisms and soil fauna, which leads to healthy crops, and consequently habitats for pollinators like bees and butterflies. The creation of healthy ecosystems benefits all wildlife, spreading beyond the boundaries of the farm and into the urban jungle.

Composting organic material

By composting organic waste urban farms are able to turn food waste into nutrient dense compost. In doing so, farms can “close the loop” on waste management, turning waste in to a valuable resource, creating a self sustaining project and reducing the volume of organic waste sent to landfills.

Storing carbon

Plants absorb carbon dioxide from the atmosphere as part of photosynthesis. In photosynthesis plants “capture” carbon in order to grow, storing it as wood, branches, and roots. Wood is especially carbon dense containing 50% carbon.

Soil acts as a carbon sink, storing carbon in the form of organic matter. Soil organic matter (SOM) is a mixture of decomposing plant and animal content, along with soil microbes and minerals. These microbes and minerals help to stabilise the organic matter and slow decomposition rates, allowing the soil to store high levels of carbon. The carbon retained from decomposed biomass in the soil gives carbon rich earth its familiar dark colour.

Air filtration

Plants on urban farms help remove pollutants and toxic particles from the atmosphere.

Plants absorb carbon dioxide and nitrogen oxides through respiration while releasing oxygen. In turn this provides more breathable air in the surrounding area. Additionally, bacteria on leaf surfaces can break down air pollutants, and convert them into less harmful substances.

Stormwater management

Plants attenuate rain water, slowing the speed that water that runs into drainage systems. Some of this water is taken in by plants for respiration and released back into the atmosphere through evapotranspiration.

Plants absorb certain pollutants as nutrients. As water moves through the soil, pollutant particles are filtered out with some broken down by microorganisms.

As a result of these filtration mechanisms, less toxins and pollutants end up in waterways, improving the health of rivers and canals in urban areas.

Challenges to urban farms:

Pollutants and contaminants:

Urban soils can often be low in quality and contaminated by high levels of chemicals and pollution. As a result farms situated inside urban areas are exposed to pollutants and chemicals from industry and emissions from exhaust.

While plants actively filter out toxins and pollution, there is a risk that some of these remain inside the plant when they reach the point of consumption. This is especially the case with soil borne pollutants.

High cost of urban farmed food

One of the aims of urban farms is to make nutritious food available to those who would be unable to access it otherwise. However, urban farmed food (especially organic produce) often comes at a premium due to the high costs associated with a farm existing in the city. These costs include things like high rental prices for land and the need to pay liveable wages in urban city centres.

Pressure for more economically profitable development

Urban farms often occupy land near city centres. As a result, this land can be in high demand, farms – especially those funded by grants and nonprofit schemes are frequently overlooked in favour of more economically profitable projects. As a result urban farms face the constant threat of closure to make way for large scale commercial and residential developments.

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This article is part of a wider series on Green Infrastructure.