Diary project reveals the true cost of growing food in an allotment

Experts from the Institute for Sustainable Food have created a first of its kind estimate of the resources needed to grow food in allotments using data from a citizen science project.

A woman is stood in an allotment next to a raised bed. There is a greenhouse in the background and several tubs of plants growing

Urban food production is an important part of making future cities sustainable and more environmentally friendly, yet it isn’t fully understood what the resource demands of growing food are in this way. With the majority of people now living in cities, urban growing has the potential to enhance food security, transform lives and improve our environment; so it is important to find out how urban food can be produced as sustainably as possible. 

In a new study published in Sustainability journal researchers at the University of Sheffield’s Institute for Sustainable Food and Department of Animal and Plant Sciences created a first of its kind estimate to understand the resource demands of typical allotment gardens over a year. The results reveal opportunities to further increase the sustainability of allotment gardening such as by harvesting rainwater at a site or community level to reduce the demand on mains water supply.

Young woman, waters herbs and plants on a urban roof garden

The hidden potential of urban food production has already shown that growing food in just 10 per cent of a city’s gardens and other urban green spaces could provide 15 per cent of the local population with their ‘five a day’. Some cities already produce a large proportion of their fruit and vegetable needs within the city limits; for example, Shanghai produces 60 per cent of the vegetables consumed by its residents.

By understanding the time and resource demand of growing in this way it is hoped the results from this study can be used to support the expansion of urban food production in our cities and give allotment holders a tool to understand and plan for the expected demands of growing food on their plot.

The team used data taken from 163 volunteer allotment diaries over the course of a year and were able to find out about a variety of resources: transportation, time, water use, inputs of compost, manure and topsoil; and inputs of fertilisers, pest control and weed control.

The diaries revealed that growing 1kg of fruit or vegetables uses an average of 24 minutes of labour, 16.9 litres of water, 0.2 litres of topsoil, 2.2 litres of manure and 1.9 litres of compost. Alongside the material benefit of providing food to eat, the wellbeing and mental health benefits of allotment gardening are well documented amongst the same volunteer group.

The team found that running an allotment over 12 months demands 87 visits, travelling an average 139 km to and from the plot. People tending to their plots also used 7 fertiliser additions; 4 pest control additions and 2 weed control additions.

Expanding urban food production would have many benefits for food security and the environment. This study provides much-needed evidence concerning the actual resource requirements of allotment gardening, revealing where opportunities exist to integrate resources into the wider energy flows of cities and improve sustainability, for example through expanded harvesting of rainwater or planning allotment sites at locations that minimises dependence on car travel to access them.”

Dr Miriam C Dobson

Lead researcher of the study, Department of Animal Plant Science at the University of Sheffield

There is growing evidence of the important role that growing food in cities and towns could play in local and even national food security. Until now we have had a relatively poor understanding of the resources required to grow this food. This study starts to build the crucial evidence base to support the sustainable expansion of urban horticulture.”

Dr Jill Endmonson

Department of Animal and Plant Sciences at the University of Sheffield

The Institute for Sustainable Food at the University of Sheffield brings together multidisciplinary expertise and world-class research facilities to help achieve food security and protect the natural resources we all depend on.

Read the full paper

Media enquiries

Centres of excellence

The University's cross-faculty research centres harness our interdisciplinary expertise to solve the world's most pressing challenges.