A new study led by Lancaster University researchers shows that urban gardens and hydroponics can thrive and may exceed the yields of rural farms. Professor Jess Davies, project lead for the Rurban Revolution project that developed this study, says, “Urban food growing is often dismissed as something that cannot meaningfully contribute to food security.”

The paper compiled studies on urban agriculture from 53 countries to find out which crops grow well in cities, what growing methods are most effective and which spaces can be used for growing. It turns out that urban yields for crops like cucumbers, tubers and lettuces can be two to four times higher than conventional farming. Cost efficiency remains an open question and important factor.

Most studies on urban agriculture focus on private and community gardens, parks and field growing operations. This one includes “grey” spaces in cities that are already built, but could be used for growing, such as rooftops and building facades.

Dr. Florian Payen, lead author and researcher from the Lancaster Environment Centre, says, “Surprisingly, there were few differences between overall yields in indoor spaces and outdoor green spaces, but there were clear differences in the suitability of crop types to different gray spaces. You can’t exactly stack up apple trees in a five- or 10-layer-high growth chamber.”