The pressure on arable land due to the expansion and creation of urban areas and increasing populations threatens food security. To address food and nutrition security, urban farming with rooftop greenhouses offers an immediate option. Urban areas often depend on food supply from rural areas, which are vulnerable to challenges such as climate change impacts, transportation challenges and economic instabilities. Urban farming with rooftop greenhouses offers a sustainable pathway towards food security improvement in urban areas.
What is urban farming
Urban farming is a localized food system where production, processing, distribution, access/consumption, and disposal/recycling of food occur in and around the city (Smit et al., 1996). It is the practice of food cultivation and distribution within urban areas. The aim is to improve food security and environmental mitigation. It is in the form of:
- Community gardening: larger pieces of land that are subdivided among several households
- Allotments: a plot of land rented by an individual for growing vegetables or flowers
- Roof-top gardening: Landscape on a multi-storey building
History of urban farming
Historically, crops have been grown in terraces and beds, as in Machu Picchu, and the tradition continues in Andean towns to date. In 1922, community gardens were used in New York. During the economic depression in Detroit in 1893, urban gardens were the only food source. Similarly, Allotments have been a food source for the community in towns and cities of the UK and Europe for the last 150-200 years. During World War I & II, communities were encouraged to produce their own food (vegetables and fruits), and some cities turned parks into farms. For instance, New York converted Central Park into gardens. In WWII, 44% of domestic production was from urban farms in Uthe SA. These indicate that urban farming has long been a sustainable tool in ensuring food security in urban areas.
Image 1: community gardening in Detroit, 1893
Rooftop greenhouses
These are structures installed on the roofs of storey buildings for the production of food in a controlled environment. The roof is flattened and reinforced with concrete to provide a platform for the installation of greenhouses for the production of high-value produce such as herbs, vegetables, and fruits.
Traditionally, rooftop farming has involved growing crops in soil-filled trays. However, soil is heavy and difficult to work with, adding significant weight to buildings. This not only affects structural durability but can also increase insurance and maintenance costs. Additionally, traditional rooftop farms are often exposed to open air, making crops vulnerable to pests, diseases, and harsh weather conditions—particularly wind, which can cause plant desiccation and damage, ultimately reducing yields.
Image 2: Rooftop farming on Changi General Hospital in Singapore using hydroponics
Today, advanced technologies offer more efficient alternatives. Modern rooftop farms can improve urban food security through the use of greenhouses and vertical farming systems that incorporate hydroponics and aeroponics. These methods are lighter, easier to manage, and provide significantly higher yields per unit area, making rooftop farming more viable and productive in urban environments.
Image 3: Brooklyn Grange Farm in Queens, New York City
Rooftop farms have significantly improved food production and supply in urban areas, helping to reduce prices by minimizing the need for importation, packaging, and transportation. As a result, consumers benefit from highly nutritious, fresh produce at lower costs. Greenhouses further enhance this by creating a controlled environment that allows for year-round food production, regardless of weather conditions, ensuring a consistent supply of fresh produce.
The Benefits of Rooftop Farming in Urban Areas
Rooftop farming contributes to more than just food security; it also offers several additional benefits:
- Water harvesting: It reduces runoff by capturing rainwater for crop production, helping to alleviate urban flooding, a common issue in cities.
- Energy savings: In tropical regions, rooftop farms can help lower energy consumption by reducing the reliance on air conditioning in buildings.
- Waste reduction: By minimizing the need for packaging materials, rooftop farming helps to reduce urban waste.
- Job creation: Rooftop farming creates employment opportunities for young people, contributing to economic stability.
Image 4: Rooftop Glasshouses in Montreal, Canada
Limitations of Rooftop Greenhouses in Urban Environments
Despite their potential, rooftop greenhouses face several challenges:
- Space limitations: Many rooftops are already occupied by essential equipment, such as chiller plants, water tanks, TV antennas, and water distribution pipes, which restrict available space for greenhouse installation.
- Crop restrictions: Rooftop farming is typically limited to crops with shallow root systems, which may not include staple food security crops like rice and maize.
- Pollution exposure: Urban areas often experience car and industrial pollution, which can contribute to an increase in insect pests that damage crops, leading to reduced yields.
- High costs: The initial installation and ongoing maintenance costs of rooftop greenhouses can increase the price of produce, making it less affordable for urban dwellers.
- Regulatory challenges: Building codes and regulations may impose restrictions on the implementation of rooftop farming, further limiting its potential.
Recommendations for Enhancing Rooftop Farming in Cities
To overcome these challenges, the following actions are essential:
- Integration into urban planning: Rooftop farming should be incorporated into urban designs and planning to optimize space utilization.
- Policy reforms: Governments should implement policies that encourage and support urban farming initiatives.
- Government support: Financial models and funding from the government can help make rooftop farming more viable and accessible.
- Technical training and awareness: Offering training programs and raising awareness about the benefits and potential of rooftop farming will empower urban farmers and increase adoption.
By addressing these challenges, rooftop greenhouses can become more vibrant and effective in tackling food insecurity.
In the current world of food insecurity, climate change, wars, environment degradation, and rapid urbanization, rooftop greenhouses offer an immediate sustainable response in building sustainable and resilient food systems in towns and cities. With advanced technologies and supportive policies, rooftop farming is the most promising future of urban food security.
References
Smit, J., Ratta, A., & Nasr, J. (1996). Urban agriculture. Food, Jobs and Sustainable Cities, Publication Series for Habitat II, 1.