

As German V2 rockets pounded London in the later stages of the second world war, one of the underground safe havens where thousands of people sought refuge was a tunnel system deep below Clapham High Street in the south of the capital.

Seventy years on, the network of tunnels is in use again but for an altogether different purpose: farming. Open the cage-style doors of the lift after descending 100ft below street level, and the modern-day visitor will find an underground farm.

Rows of shelved beds for growing salad leaves and herbs line an expansive cavern. The plants will soon be harvested, to be delivered to top London restaurants within a few hours of being gathered.

The tunnel area – one of a network of seven built under Northern line stations between 1940 and 1942 – is home to Zero Carbon Food. The company has developed the city farm under the homes and businesses of Clapham and is expected next month to start selling so-called “microgreens” – the shoots of plants such as coriander and rocket, which carry an intense flavour.

Friends and founders Steven Dring and Richard Ballard are using hydroponics – the system of growing plants without soil – to create a hi-tech farm that cuts down on the food miles bringing food from harvest to plate and improves freshness.

Facebook Twitter Pinterest The underground tunnels in Clapham, south London. Photograph: Alicia Canter/The Guardian

Seeds are planted in a wood fibre pulp for an initial few days before being transferred to shelving units under banks of LED lights. The lights are on for 18 hours a day while strong fans maintain the temperature at between 21C and 23C. When the system is fully up and running, the plants can be harvested after between six and 28 days, depending on the plant, before being packed and sent off to market. The process then starts again – underground farms, unlike farms above ground, operate throughout the year.

Microgreens are the early stages of plants more commonly harvested when they are more fully grown. They are popular with chefs for their deep flavour.

“The restaurants like them for having very little on the plate that packs so much taste,” Ballard says.

Ballard and Dring have been working on the project for the past three years. They hit upon the idea after Ballard worked on a film about hidden parts of London. After Transport for London (TFL) gave them a tour of the underground space in 2012, they carried out test growing in another of the tunnels before embarking on the project.

The company, which operates under the Growing Underground brand, will initially be selling eight different microgreens including celery, mustard, radish and coriander. The founders claim there is an eager clientele of chefs around the city who are undersupplied at present with produce, meaning that often the produce is 24 to 48 hours old by the time they receive it.

Facebook Twitter Pinterest The underground LED-lit growing beds. Photograph: Alicia Canter/The Guardian

Punnets will be boxed in groups of four, moved up the lift and taken straight to the market.

“That comes with benefits with regard to food miles [and] freshness of product. We can cut and produce the product into a box and get it into New Covent Garden market within four hours and it will obviously last longer,” Ballard said.





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The first section of the tunnel system they have converted now extends to 6,000 sq ft (550 sq m) of growing area and will be able to produce 700 boxes of goods a day when production has been fully scaled up, says Dring. They hope to extend this to 23,000 sq ft (2,200 sq m) of growing space within two years.



“Anything that grows within 30 days is financially viable. After you go over the 30 days, it is not so. That is changeable a bit now and the efficiencies are changing so you can bring crops that you would have done in 40 days down to 30 days,” Ballard says.



The market for the microgreens is young, he adds, but the company can switch to other produce once it can be grown under the 30-day ceiling. “We can turn these around very quickly and that is why we have chosen microgreens.

Facebook Twitter Pinterest Richard Ballard and Steven Dring. Photograph: Alicia Canter/The Guardian

“LEDs are in their infancy in technology, like the mainframe computer in the 1960s, so these are only going to get more and more efficient.”

Their market is mostly limited to restaurants at present, says Ballard. “With all the programmes on TV, this is going to filter down to the general public more, they will demand these things. It is not quite there yet.”

He adds: “There is an element that microgreens are a trendy product but they are in their infancy and it is something which is not going to go away … We can grow coriander as a herb [and] we can grow baby leaf, which are the staple products in the market, but we are focusing on the microgreens first because we know [chefs] are running out of them every day. So if we can produce that to start with, then our next stage might be baby leaf.”

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The problems they encounter affect all farmers, however, in that they are “still dealing with nature”, says Ballard, although in Growing Underground’s case, a failed crop can be replaced very quickly because of the quick turnaround time.

A prominent backer of the company is former Masterchef judge and Michelin-starred chef Michel Roux Jr, who hails from the area – the tunnels run partly under Clapham Common, where he played as a child.

The company has so far raised £850,000 and expects sales in the first year to reach £1.25m. Possible future sites for the same concept have been suggested for tunnels in Antwerp, Germany and across Scandinavia.





Microgreens on the menu

Although the delicate greens may look like a simple garnish, they have an intense punch of flavour coveted by chefs. Supplies in the city regularly run short, according to Ballard.



The microgreens are seedlings of plants which are harvested before they are fully grown and contain the essence of the flavour of the fully grown plant but in a concentrated form. Home gardeners can try their hand too, with salad crops such as rocket and pak choi, sunflower shoots, pea shoots and mustards, as well as herbs such as basil and coriander able to give any salad an extra injection of taste.



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