Nature Food: CPULs enable the spatial integration of urban horticulture.

We were very interested to read a Perspective article, The hidden potential of urban horticulture, in the March 2020 edition of the journal Nature Food. The article by Jill L. Edmondson et al. from the University of Sheffield, UK, assesses the potential contribution that urban horticulture (UH) can make to the fresh fruit and vegetable needs of the City of Sheffield. It contends that ‘Urban areas offer considerable potential for horticultural food production, but questions remain about the availability of space to expand urban horticulture and how to sustainably integrate it into the existing urban fabric.’ The authors ‘explore this through a case study which shows that, for a UK city, the space potentially available equates to more than four times the current per capita footprint of commercial horticulture. Results indicate that there is more than enough urban land available within the city to meet the fruit and vegetable requirements of its population.’ Based on their case study, the authors ‘propose a generic conceptual framework that identifies key scientific, engineering and socio-economic challenges to, and opportunities for, the realization of untapped urban horticultural potential.’

This well-researched article reminded us of our 1998 entry to the EU-wide Europan architectural competition where we carried out one of our first design research studies looking at how urban agriculture could positively contribute to food security, environmental impact and the quality of space and place at Sheffield’s Manor Estate. Jill L. Edmondson and fellow authors of The hidden potential of urban horticulture echo many of the insights we gained from developing our Europan entry. Their research method also has similarities to the Diggable City report (2005) from Portland Oregon, USA, which undertook a spatial inventory of potential food growing sites in that city’s urban and peri-urban areas.

The University of Sheffield’s study differentiates between soil-based horticulture and environmentally-controlled horticulture, e.g. rooftop greenhouses for hydroponic growing.  It found that the total area of open space, including gardens, peri-urban open space and urban rooftops deemed suitable for horticulture could supply all of the cities “five-a-day” fruit and vegetable needs. If 10% of open space and suitable rooftops became productive, it estimates that these could supply about 14% of the city’s needs with allotments contributing an additional 3%. These figures are comparable to our estimates.

The article concludes that ‘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. Public engagement is also critical, detailed local insight and mapping of opportunities can enable people to envision their environment differently (for example, the Edible Map Project; http://mikeytomkins.co.uk/category/maps). It will require sustained effort to achieve this potential, but delivering more of it could significantly improve urban food security, alongside other ecosystem service benefits in urban areas.’

Article published in the journal: Nature Food, vol 1 (2020), pp. 155–159, Online at: <https://www.nature.com/articles/s43016-020-0045-6>, see here.

For more information on the Continuous Productive Urban Landscape concept see here.

Image: Bohn&Viljoen’s 1998 proposal for integrating urban agriculture into Sheffield’s Manor Park estate (source: Bohn&Viljoen Architects 1999)