Growing Underground - Food beneath our Feet | Garden Visit

Growing underground sounds ridiculous. Plants need light, air, water, nutrients to grow. They use sunlight to create energy (ie the process we call photosynthesis).

Even when we grow, in order to eat, the swollen roots and underground stems of certain crops – tubers such as potatoes and root crops like parsnips – they have foliage that grows above ground.

Have you sat down and thought about the part of the plant you’re eating? We eat a lot of the above ground top growth of food plants. For example: –

Leaves – lettuce, cabbage, spinach; lots of herb leaves
Flowers – broccoli, caulifower
Seed pods – mange tout peas, asparagus peas
Seeds – runner beans, broad beans, peas

You may be thinking that in commercial greenhouses they use extra light, water to help produce crops. But these are still growing above ground, even if, as in the case of hydroponics, the ground isn’t soil. The crops are being grown on the surface of the earth not below it.

Herein lies the adventure of a garden visit with a difference…

The Journey Begins

Consider a damp December afternoon in South London, with shoppers busy looking for Christmas presents as well as the usual birthday gifts and necessities for twenty-first century life. Friends are meeting for coffee and a chat. Cars and delivery vans trundle along the road, stopping for beeping pedestrian crossings with their engines rumbling: its not worthwhile putting on the handbrake.

You turn off the busy main road into to find your destination – a short metal staircase leading to a door in a fairly nondescript building. Only the sign on a air vent column ‘Growing underground’ gives you any clue that you’ve reached the right place.

Inside, you’re led through a corridor to a small waiting room, Ah, faces you recognise! Some members of the Chartered Institute of Horticulture, Southeast branch. And look! There’s a map on the wall showing the tube tunnels that were used for air raid shelters. Then in comes Richard Ballard, one of the founders of Growing Underground, to tell us how this new agricultural revolution began.

Sparks of inspiration come from many places and one of the leading ones was the concept of future digitised cities as part of the Third Industrial Age. How would we eat? What would the effects be on farming and food production? What changes need to occur? Vertical farms, growing food inside using hydroponics, both these techniques were added to the mix of solutions, but had already been done. What about something more radical?

Growing Underground – Food beneath our Feet

During the Second World War these air raid tunnels had provided a safe place for Clapham residents. Since then they had been used for various purposes, one of which was as a document store in the drier tunnel areas.

A complicated ownership and permission finding search eventually led to these basically disused tunnels being leased to Richard and Steven. And in them they grew the first plants they had ever grown. (And this despite their parents gardening on allotments).

Experimental at first, the farm was moved to other tunnels in the complex which were in better condition. The aim was to provide a ‘field to fork’ product, guaranteeing quality and process. Different types of food crop were grown to discover which were best suited to these conditions. Tweaks to pH levels, growing media, light levels and density of sowing needed to be made. The harvested greens also had to maintain their freshness during transport.

The farm has two levels, the upper office level, a mezzanine with water storage tanks and so on, and the lower, production level. Talk over, it was time to make our way down the 180 winding stairs to the lower levels (or take the lift).

Going Underground to Growing Underground

Into our PPE gear (NB if you have small feet get to the front of the queue) and into the magical world of pink lighting, whirring of fans and a fairly steady temperature of 15 degrees C.

The seeds are sown onto mats, labelled and placed in trays on shelving. There’s row upon seemingly endless row of stacked shelves humming with busily growing greens. There are nasturtiums, lettuce, broccoli, red cabbage, coriander, garlic chives and more. Yet currently only about 20% of the available space is used for farming. They are planning to expand the growing underground areas along the tunnels to cover 2500 square metres.

As the longer term aim is to be zero carbon and organic there is plenty of recycling going on where possible. For example, the growing mats are recycled after use as re-using gave rise to issues which affected the quality of the next batch of micro greens. The tunnel environment is controlled and manages to be pest and disease free as a result. They’re still working on the nutrients being purely organic.

broccoli micro greens, growing underground

tunnels, fan, led lighting, growing underground

Oh yes, nutrients. Those seeded mats in their trays are given the correct measured dose of nutrients in the water thanks to a semi-automated process. When you’re aiming for a seed to harvest period of 8 – 20 days (depending on the crop) you’ve got to get it right!

Down in the tunnels, the growing micro greens are unaffected by the weather and seasonal changes. They have LED lights to provide both warmth and light – the essential catalyst for photosynthesis. But they get night-time too, and the overall temperature drops a bit then. Humans make sure everything is running smoothly, checking equipment and lifting mats to observe root growth.

Underground Harvests

At harvest time the stems are sliced and the crops released from their carpet bed. For a micro green such as popular pea shoots, they can harvest about 2500 from per square metre every 8 days or so. That’s about sixty harvests per year.

This could well be one of the ways we farm in the future. Hydroponics uses much less water than traditional open field farming, averaging around 70%. It is a system becoming more widely used in countries with low rainfall for that reason.

This underground farm produces about 15000 punnets daily for supermarkets and restaurants in the Greater London area. Even during the Coivd-19 lockdown, staff were working, spit into two teams. Priority was given to wholesome greens for keyworkers.

And they are very tasty – we tested them 100 foot below ground. And “us horticultural visitors” wended our way home each with a 80% recycled plastic punnet filled with futuristic food for our suppers.

Are we in a new agricultural revolution?

This place never closes, whatever the weather, the season, the time of day or night, there are always food crops growing underground in Clapham. As for me I pondered on this thought as the tube rattled its way under more of London’s streets . We need to find new ways of growing food for many reasons. And whilst a tub of micro greens on its own would not sustain a gardener after a hard day’s physical labour, it would definitely provide the freshly picked salad element.