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Hidden Depths

Elizabeth Lloyd-Owen28 July 2016

Clapham High Street isn’t the first place that springs to mind as a location for a farm. Visitors making their way along the busy pavement to a cookery class at Cactus Kitchens would be astonished, as were our team when we visited, to learn that far beneath their feet a vast and varied crop of micro greens is sprouting.

Moments away from the Cookery School, 129 steps spiral 33 metres underground to a vast system of deep tunnels connected to Clapham North tube station. On the surface, the only clue to the farm’s existence is a discreet, grass-roofed air shaft tucked back from the road. Below, lies a pristine, twilit world, inhabited by white-suited and booted figures tending to an abundance of green shoots that have never seen the light of day. Welcome to Growing Underground.

Michel Roux Jr is a co-director and enthusiastic backer of this innovative, sustainable urban farming project that uses hydroponics (growing plants without soil) as its means of production. Part of the attraction is that the diminutive greens cultivated here (including mustard seed, red amaranth, Thai basil, radish and watercress) can be in the kitchens of Le Gavroche, only a few miles away, within four hours of being harvested.

Growing Underground was brought to life by friends Rich Ballard and Steve Dring who saw the chance to test their ideas about sustainable farming and clean agriculture in the network of empty tunnels. Owned by Transport for London and dug in WW2 as air-raid shelters for 8000 people, post war plans to incorporate the tunnels into the Northern Line were abandoned for lack of cash. Now 550 square metres are in use for cultivation and that area is expanding.

The Cactus Kitchens team travel underground in a scissor-gated lift, don spotless white lab coats, rubber boots and blue hair nets and venture onto the farm.

This scrupulously clean, odourless environment seems so far removed from nature it’s a marvel anything grows here at all. Traditional pests, rats for instance, and insects that are the bane of farmers above the surface, simply don’t venture this far down. The muffled rumble overhead is a tube train passing a few metres above us. But crunching on a handful of just-picked garlic chives bursting with flavour and a few tiny shoots of intensely aromatic sprouting fennel convinces us there is nothing artificial or unnatural about these subterranean crops.

The environment in which crops are grown underground might seem the antithesis of what is most prized by consumers - free range, organic, natural, but this operation doesn’t compete for space in an overcrowded landscape, is entirely sustainable, doesn’t waste water or squander food miles - all the crops are destined for customers inside the M25. The project’s biggest cost is electricity which Growing Underground purchases from a renewable energy supplier.

The micro greens don’t have organic status (growing in a medium other than soil makes them ineligible), but they are grown year round in a pesticide free environment at a controlled temperature of 23°C, and not subject to extremes of weather, making this method of cultivation highly efficient and low waste. Hydroponics uses 70% less water than traditional open field farming; 90% of the water used is recycled in a closed loop system. Unlike traditional farms there is no agricultural runoff.

Despite its futuristic appearance this farm relies on surprisingly low-tech methods and tools: tonnes of recycled carpet, metres of cling film, plastic buckets, metal trays and catering trolleys and avenues of shelving. But new technology, crucially low energy LED lighting, makes this farm possible.

The life cycle of a micro sprout is rapid. From first sowing, tiny coriander shoots take about four days to appear, pea shoots about 48 hours. Depending on the variety of plant germination to harvest takes from 6 to 28 days. To speed up germination, peas and coriander seeds are soaked in buckets of water for 48 hours to which sodium hydrochloride has been added to eliminate pathogens and e-coli.

Seeds are sown on trays of recycled carpet and kept moist under cling film in a darkened, womb-like tunnel. Once the plants have germinated they are wheeled to the farm tunnels where they are grown stacked on shelves under LED lights and irrigated by recycled water to which nutrients have been added.

Later, after each crop is harvested the discarded carpet seed beds are dispatched to a biomass plant whose energy helps to power east London. Whilst hydroponic farming can’t feed the world, it is addressing the problem of sustainable food production.

Once futurologists predicted that labour-intensive meals would be replaced by pills. Instead, our eating habits are becoming ever more diverse, and chefs ever more inventive; there’s never been more interest in the provenance of our food or disquiet at industrial farming methods. Agriculture is the third largest contributor to global warming. Hydroponics, not food capsules, is a taste of the future.

Producing up to 2000, 30g packs of greens a day, Growing Underground accounts for a tiny percentage of London’s expanding microgreens market. But these dainty shoots punch well above their weight on the plate and for the time being, Michel Roux Jr and his fellow chefs can’t get enough of them - and you too could taste them on a cookery experience with us.