An abandoned World War 2 bomb shelter, deep below the busy streets of London, may not seem like the ideal place to set up a farm. But that's exactly what a team here has done, using modern hydroponic farming methods and the latest LED technology.
Run by Growing Underground (part of the Zero Carbon Food company), the project aims to grow crops in the most environmentally friendly way possible. The water for the crops is on a constantly recycled circuit and the tunnels remain at a constant temperature so don't need to be heated.
The closed environment of the tunnels also means pests aren't a problem, which in turn means that no pesticides are required. And thanks to the farm's location, there's minimal travelling required for the crops to reach restaurants across London.
The farm is both a proof of concept -- showing that food can be grown in what seems like such a hostile environment -- and a commercial business. Various restaurants take deliveries from Growing Underground and top chef Michel Roux Jr is on the company's board.
Instead of beds of soil, the crops are grown using hydroponics, where they grow in water. The plants only require a small amount of material for the roots to grip on to -- in this case, recycled rugs -- and are fed a precise amount of nutrients through a carefully monitored water system.
It uses a system known as "ebb and flow" in which the whole bed fills with nutrient-rich water that then slowly drains out, ensuring the plants get the food they need but aren't left standing in stagnant water.
Most of London's shelters are dotted along the Northern Line -- the farm itself regularly rumbles as tube trains pass overhead. The majority of shelters are accessed through stations, but the farm has its own dedicated entrance, so the team doesn't have to battle their way through ticket barriers carrying supplies every day.
There's no natural sunlight of course, so the lab is rigged up with a host of LED lights.
The constant conditions in both light and the 16C (61F) temperature means that crops can be grown all year round. Traditional horticulture can at times be difficult as often unpredictable weather patterns -- in part a product of climate change -- means that crops can be easily lost.
The Growing Underground team are able to constantly monitor their plants to ensure conditions are always optimal. Many of their plants are able to go from seeds to being harvested in 10-15 days and can achieve several crops in a month -- both quicker and more reliable than traditional farming methods.
Different LEDs have different wavelengths and that can change how the plants respond. Some radishes grew with a darker colour under some lights, for example.
Does growing under LEDs, rather than natural sunlight, result in lower nutritional values from the crops? Not according to farm manager Gabriel De Franco, who explains that micro crops such as these already have higher nutritional value than their larger counterparts and are higher in antioxidants.
Various types of plants are being grown in the tunnels, including rocket, mustard, coriander and Thai basil.
Growing Underground promises that no crops will be delivered outside of the M25 motorway that encircles London. The travelling would not only have a carbon impact on the environment, but detract from the freshness of their products. Growing Underground claims its crops can be picked and delivered to the kitchens in only four hours.
All crops are being grown in their micro forms, as full-sized plants would require deep beds for their roots. Many of them, therefore, look like rather less interesting watercress.
I had a taste of the coriander and mustard plants. The flavours were intense, but not overpowering. Their size of course means they won't be the main event in any meal, but will be used to add fresh flavours.
Although using completely organic techniques, the food can't be officially certified as organic as only crops grown above ground qualify. This may be changed as underground farming becomes a more common practice.
Growing Underground leases the tunnels from Transport for London, the city's transit authority. Only a small section is currently used for growing, but the team hopes to expand along the tunnels with future investment.
The tunnels are all drilled as round tubes, so the flat surfaces you walk on are mostly false floors. Beneath those floors is the other half of the tube, which would make perfect storage space for a larger farming project. Or, as I suggested, a skateboard half pipe.