A network of tunnels 33 metres under Clapham in London, originally built as a WWII bomb shelter, is being used to grow a range of different salad vegetables destined for Londoners' plates.

Gallery: Vast underground bomb shelter reappropriated by urban farmers Gallery Gallery: Vast underground bomb shelter reappropriated by urban farmers + 6

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This week, Wired.co.uk paid a visit to the subterranean farm, descending the winding steps deep into the bowels of southwest London. The space is enormous. It's made up of two seemingly never-ending tunnels (actually 430 metres long), lit -- at least during our visit -- only by the torches of Steven Dring and Richard Ballard, the founders of Zero Carbon Food, the company behind this agricultural curiosity.


The space -- owned by Transport for London -- has been lying dormant since WWII, when it was used as a bomb shelter that could accommodate 8,000 people. There have been occasional requests from ambitious club promoters to host parties in the tunnels, but the lack of appropriate fire escapes makes it an unfeasible venue. But not for plants, it seems.

The end of one of the tunnels is illuminated, providing a ghostly glow that seeps towards us. Behind a plastic curtain we find the "farm", a small test area within the vast square metre space where broccoli, pak choi, pea shoots, rocket and red lion mustard are all being grown using hydroponics and LED lights.

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[Quote##"The biggest misconception is that this is frankenfood. But what people don't realise is that a lot of our food is already grown using hydroponics"##Steven Dring##Company¬Zero Carbon Food##Id¬9w2vg]Zero Carbon Food and was launched by Dring and Ballard -- who have been friends since school --- with the aim of using redundant underground spaces to produce leafy greens, herbs and microgreens for sale within the M25, using 70 percent less water versus traditional open-field farming methods and providing year-round production, reducing food miles for retailers and consumers. The food -- which is grown free from pesticides -- will be sold to restaurants, wholesalers and, eventually, through a consumer-facing brand called Growing Underground.

Olivia Solon


The idea was borne out of a pub conversation around urban farming. Ballard was studying for a film degree, while Dring was working in logistics. As part of his degree, Ballard had been working on a film about the democratisation of energy, exploring the world's dwindling natural resources and experiments in sustainable energy from around the world. "We are both of the opinion that we will run out of natural resources and fossil fuels, so we wanted to build a future-proofed business," Dring told Wired.co.uk.

Both Dring and Ballard felt that although there was a lot of talk about urban farming, particularly vertical farming, there had been very little large-scale action. It was something that would happen "in the future", but not now. They sought to change this. "We want to avoid doom porn. We are just getting on with it and trying to grow stuff underground," Dring adds.

London's population will grow by 24 percent over the next decade, so finding new food sources is important. Urban farming above ground simply wasn't cost-effective: real estate, particularly in London, is too costly. But underground was another matter. Space was cheap, if a little eerie. TFL allowed the team to test whether the space was viable before they signed up to a 25-year lease.

The test area comprises of five growing beds, covered with a substrate -- they've experimented with coconut coir, hemp and carpet -- onto which the seeds are sown. The base of the substrate gets flooded by an ebb and flow system to provide moisture and nutrients a couple of times a day. Overhead are configurable LED lights that can be tweaked according to the specific light requirements of the crops below. The LEDs stay on for 18 hours per day; the residual heat brings the tunnel temperature up from 16C to 20C -- creating the perfect, consistent salad-growing environment, 365 days of the year. It occurred to Wired.co.uk that it would also offer up the perfect, discreet marijuana-growing environment; Dring and Ballard say they've turned down an extremely generous offer from someone who had the same idea.

The project has been endorsed by celebrity chef and board member Michel Roux, who was drawn to the idea of reducing the time from harvest to table as well as the prospect of being able to grow "trending" crops to order. On a recent trip to Asia, Roux identified micro pak choi as a trending vegetable, for example. The farm would also be able to grow "heritage crops" -- tastier species that aren't produced en masse because they spoil too quickly, for example. Neil Sanderson, the MD of salad giant Florette is also on the board as a non-executive director. "The biggest misconception is that this is frankenfood. But what people don't realise is that a lot of our food is already grown using hydroponics," explains Dring.


One might question how growing crops using artificial light could be considered a sustainable alternative to growing crops outside, as nature intended. However, the founders point out that many vegetables are grown in greenhouses which require either energy-intensive lights or heating systems. The LEDs being used in the tunnels are energy efficient and last for nine years. Any additional power is sourced from Good Energy, while the company is exploring other power options including recycling heat from the Northern Line.

In order to take the farm up to full capacity, Zero Carbon Food is raising £300,000 on crowd equity site Crowdcube. (Unusually for an agricultural project, Zero Carbon Food has managed to attain EIS and SEIS approval, meaning that investors in the company benefit from tax relief.) This will fund the installation of the equipment, which will eventually see the tunnels flanked on both sides by three-tiered growing beds, to form 10,000 square metres (3.5 acres) of growing space. More of the work will be automated -- such as seeding and cutting -- and the team will expand to between 15 and 22 people.

If the funding target is reached by March, the farm should go into large-scale production by September 2014. By then, hopefully, there will also be a lift to carry produce out of the ground. Those 179 steps back up to ground level are a killer.