The answer no longer lies in the soil

The Covid-19 pandemic has given a big boost to advocates of vertical farming because of the simplicity of its supply chain.  Vertical farming is the practice of growing crops in stacked layers without solar light.   It can be housed in buildings, shipping containers, underground tunnels and even abandoned mine shafts.  Vertical farms use soil-free growing techniques and stack crops in specially designed beds and trays.

The technology

It makes use of LED lighting to provide different wavelengths of light, according to crop and growth stage need.  The sector received a boost from advances in LED lighting.  The lights can be used to change the way plants grow, when they flower, and how they taste.

The LED lights can be positioned between plants and produce hardly any heat radiation.

The benefits

Advocates say that vertical farming offers a means of guaranteeing yields and reducing the industry's environmental impact while improving the supply of safe, healthy and nutritious food.   There is lower water and nutrient use.

Crops can be grown year round with minimal human intervention.   It can be run entirely on robotics.  This is an important consideration when reliable labour is scarce and its cost is rising.

There is a reduced need for transport and a reduction in food waste because crops are of a more uniform quality.  Reduced fertiliser use means reduced greenhouse gas emissions.

Downsides

In a field, the sun comes free.  Vertical farms are energy intensive and have high electricity bills,   However, there are improvements under way in LED lighting.

It also requires a high initial capital investment and the sector has been littered with bankruptcies.

It is only suitable for a limited range of crops.   It makes sense to grow high margin crops.  Examples are leafy greens, baby leaves like pak choi and herbs such as basil.  It is of no use for staple commodities like bulk grains or cereals.

The sector

Worldwide it was worth £1.72bn in 2018 but is predicted to rise to £9.84bn by 2026.   Japan and the United States have been leading the way.

Intelligent Growth Solutions have a demonstration farm near Dundee.  The company raised £7m from three venture capital firms and the Scottish Investment Bank.   They sold their first vertical farm in July to an Aberdeenshire venture backed by a founder of craft brew business BeerDog

Ocado has invested £17m in the sector.  It has a joint venture with US firm 32ha and Priva Holdings in the Netherlands known as Infinite Acres.  It has also taken a 58 per cent stake in Lincolnshire's Jones Food Company.

In London Growing Underground provides microgreens and salad greens beneath the streets of Clapham.

Advocates argue that vertical farming is disruptive in the true sense of the word as it is changing conceptions of what the food system should be like.