'The UK imports more than half its salad leaves from Spain and Morocco; an estimated 60% is thrown away': Can vertical farming solve Britain's self-sufficiency problem?

Inside the lofty walls of a building beside the River Severn, small miracles happen daily. Stacked on Meccano-style shelving, 15 layers high, are trays of miniature salad leaves and herbs bathed in the disco glow of multicoloured LED lights.

Seeds started on a substrate of sheep’s wool and recycled plastic and fed from tanks of nutrient-rich water grow into plants ready to harvest in 10 days. Hot air is recycled as cold; water transpired by the plants captured and returned to the tanks with liquid CO2 from anaerobic digesters to boost growth; forklifts trundle silently up and down the aisles shifting trays.

This is vertical farming, a highly automated, computer-controlled cultivation model still in its infancy, but developing rapidly. ‘On our four-acre site, we grow the equivalent of what would require 800 to 1,000 acres of land in conventional farming,’ says James Lloyd Jones, founder and CEO of Jones Food Company (JFC) near Lydney in Gloucestershire. ‘We don’t use pesticides or herbicides, only a few good bugs, such as parasitic wasps, to deal with any aphids.’

The result is bagged baby leaves grown year round and available on supermarket shelves within days of harvesting. Currently, the UK imports more than half its salad leaves from Spain and Morocco; an estimated 60% is thrown away. ‘It is a highly perishable crop,’ explains Lloyd Jones. ‘A lot goes off because it takes so long to travel. We don’t wash our leaves, so they stay fresher for longer and have higher trace elements and nutrients.’ We walk down the aisles, sampling as we go: sweet chard; texel, a garlicky kind of kale; bulls’ blood tasting like beetroot — these perky little neonates are delicious.

In the processing hall, trays roll down a chute where the base and root layer is sliced off, the leaves tumbling down to waiting packers. ‘Currently, the waste is burnt,’ Lloyd Jones admits, ‘but we are developing a biodegradable composting method.’ The farm’s high energy needs are supplied by solar panels on the roof and bought-in renewables. JFC supplies Ocado and Booths, the Waitrose of the north, with its Leaf brand of bagged leaves and herbs; its Homegrown brand is sold in Asda for £1 a bag. ‘We grow a high-volume, low-value product that suits the UK market,’ asserts Lloyd Jones.

Leafy greens alone are not going to feed the world but, says Zoe Harris, director of the Centre for Environment and Sustainability at Surrey University: ‘Vertical farming can increase food production and resilience within UK supply chains. It can cut food miles, decrease reliance on imports and be more sustainable than field production. It is a closed-loop recirculating system, re-using water and fertiliser many times without any effluent run off, and it is not vulnerable to extreme weather events.’

The vertical farm company GrowUp started life in a greenhouse on top of a shipping container parked near Borough Market, London SE21, with founders Tom Webster and Kate Hofman delivering salad leaves by bicycle to local restaurants. They then took over a warehouse further east in Beckton, E6, and kitted it out as a vertical farm producing micro greens and herbs. ‘We had a niche market of small, high-end customers,’ recalls Webster, ‘but decided we need to focus on producing bagged baby salads for the mass market.’

Two years later, they launched their current site, Pepperness in Kent, with a £100 million investment from Generate Capital, a US public-benefit corporation specialising in sustainable agriculture infrastructure. Their Unbeleafable range now sells in Tesco, Sainsbury’s and the Co-op; their Fresh Leaf brand goes into Iceland and Spar at a lower price point.

Vertical farming is still in its emerging stage and there have been some spectacular failures, due partly to high energy costs and faulty business models. There is currently no Government support for the industry, despite it being cited as the future by Michael Gove during his tenure as Defra Secretary — it is not eligible for any of the recent environmental incentives. However, at former Prime Minister Rishi Sunak’s Downing Street Farm to Fork summit a year ago it was acknowledged to have a role in a future food system. Meanwhile, the UK’s biggest player, Fischer Farms in Norwich, Norfolk, its environment designed ‘to emulate a Tuscan hillside, with the warmth of sun and slight breeze’, is sending out up to 1,000 tons a day of leafy greens and herbs.