Vertical farming ‘greener than first thought’, study finds

A new study from the University of Surrey and the University of Aberdeen has revealed that vertical farming methods could help reduce the overall impact of farming on the environment.

Researchers studying a vertical lettuce farm in the UK found it was no worse for the environment than growing lettuce in fields, and could save 8,000 hectares of land.

Growing lettuce on stacked shelves in high-tech greenhouses produced the equivalent of 740g of carbon dioxide (CO2) per kilo of lettuce, the study found. This was comparable to growing in a field while using much less land.

Meanwhile, electricity use made up nearly 40 per cent of the farm’s total climate change impact – a factor that could be reduced by using renewable energy resources, the researchers said.

Co-author of the study and a senior lecturer at Surrey’s Centre for Environment and Sustainability, Dr Zoe M Harris, said: “Our findings show that vertical farms can help reduce the climate impact of farming, especially if their electricity comes from renewable sources.

“Vertical farming uses about 28 times less land than traditional farming methods. If all lettuce fields were replaced with vertical farms, we could save over 8,000 hectares in the UK alone.

“That could free up land to grow other crops. Vertical farms can also be built in cities, significantly reducing the impact of transporting the crop to the people who eat them.”

She added: “Our study is an important first step towards demonstrating the impacts of vertical farming being greener than first thought, despite only having a limited data range available.”

In vertical farms, shelves of crops like lettuce or herbs are stacked on top of each other in a controlled environment. Plants can grow without soil – drip-fed with nutrient-rich water or even with mist sprayed onto their exposed roots.

The researchers also studied other environmental impacts like land use, water use and water pollution.

Michael Gargaro, a researcher at Surrey’s Centre for Environment and Sustainability, commented: “One of the biggest environmental impacts came from the jute plugs the lettuce seeds are grown in. They made up 18 per cent of the climate change impact, as well as the lion’s share of the water pollution and land use too.

“Using another material could make a vertical farm even more sustainable. Future research should consider alternatives like coconut fibre, hemp or perlite.”

He added: “We hope this study inspires further research into the sustainability of the food sector.”