A recent study was conducted in the UK about the hidden potential of urban horticulture and how it could best be implemented into existing landscapes. Researchers from the Institute for Sustainable Food at the University of Sheffield recently had this work published in the research journal Nature.
They began by using a geographic information system (GIS) to map current green infrastructure being used for urban horticulture (UH) then looked at parks, gardens, woodlands, and finally grey infrastructure, such as buildings to determine just how much it’s possible to expand the UH system in their hometown of Sheffield.
Lead author of the study an Environmental Scientist from the University of Sheffield, Jill Edmonson talked about the benefits this would bring:
At the moment, the UK is utterly dependent on complex international supply chains for the vast majority of our fruit and half of our veg – but our research suggests there is more than enough space to grow what we need on our doorsteps. Even farming a small percentage of available land could transform the health of urban populations, enhance a city’s environment and help build a more resilient food system.
Taking into account key scientific, engineering, and socio-economic challenges, they looked at two different forms of UH: controlled environment horticulture (CEH) on flat roofs and soil-based horticulture (SBH) within the green infrastructure.
Controlled Environment Horticulture
Flat roofs cover 24% of the buildings in Sheffield and the expansion of green infrastructure will mean that not all of the space can be used for CEH purposes, it ends up equating to .5 square meters per person. That space would allow for year-round cultivation using harvested rainwater for irrigation and minimal lighting requirements. Growing methods like hydroponics and aquaponics could be used for high-yield, high-value crops.
The paper points out that although this doesn’t sound like much growing area, “The high-yielding nature of CEH production systems and focus on specific crop types could nonetheless contribute substantially to the city-wide UH potential.”
Soil-based Horticulture
The researchers went ahead and took into account just how much food could be produced if they used 100% of potential SBH land within the city. They said this could feed approximately 709,000 people per year on a ‘5 a day’ diet, or 122% of the population of Sheffield. They went on to report:
More realistically, if SBH was practiced in 10% of domestic gardens and expanded into 10% of the additional land identified in the GIS, it could feed 12% of Sheffield’s population per year (15% in total including allotment land now in use).
Urban Horticulture Future
Using both systems together is the optimal solution for cities. The researchers determined that overall there is “considerable production potential” for SBH to cover the fruits and vegetables needed for the city’s population. CEH could be used more specifically for high yield crops in smaller concentrations, but more research and growing is necessary to truly know just how big of an effect the CEH could have.
As more cities around the world begin implementing urban horticulture practices, they will be able to share data and information for the best practices. Advancements in technology and computer automated smart UH growing systems will further promote diverse food production practices.
In conclusion, the researchers talked about how UH will take a combined effort where among other things public engagement is critical in how they wish to see their environment:
For UH production to expand sustainably, a more widespread understanding of its potential amongst urban planners, policymakers, and businesses must be fostered. Such understanding may be enhanced by the use of demonstrator SBH and CEH systems. While our conceptual model highlights the diverse forms of UH that may be effective in urban systems, this understanding must also draw on frameworks that emphasize the spatial integration of food production, such as the Continuous Productive Urban Landscapes concept.
209 cities around the world are now part of the Milan Urban Food Policy Pact that commits them “to develop sustainable food systems that are inclusive, resilient, safe and diverse.” It also encourages the promotion and strengthening of urban food production.
