Future food from fish tank farms

A grey haired woman eyes the neat patchwork of micro greens, nutrient rich pea-shoots, wheatgrass, basil and cress and asks if she could grow them in her flat. Her question is fielded by Dermot O’Regan, a partner in Grow Bristol – a new enterprise pioneering aquaponics for urbanites. Yes, in fact we all could, with a bit of training and a fish tank. This is potentially part of making a sustainable food future for us city dwellers. The woman tastes some snippets from Grow Bristol’s kale, radish, rocket and mustard greens on display at Bristol Food Connections event at College Green. 

She doesn’t inspect the model vertical ‘farm’ – it looks artificial. It features a cascade of gutters with plant plugs under grow lights, leading to a water tank inhabited by a small, blue plastic fish (later replaced by five live goldfish). 

Grow Bristol partner, Peter Whiting, explains how their final version will use Tilapia fish – and the fish’s nitrogen-rich waste used to feed water-grown salad plants and herbs. They will be certified by CEFAS – the government fisheries agency.

The Tilapia are the second most commonly farmed fish worldwide after carp. In Bristol, they will be sold on to restaurants and fishmongers – as well being part of Grow Bristol’s pee-cycling system. The idea to combine a fish-and-salad growing system for city spaces grew over a few pints between the two friends.

Peter a horticulturalist and gardener has known Dermot for over fifteen years. Dermot was ready to move on from his Environment Agency desk job. Both men felt that sustainable local food production should be made possible for individuals as well for organisations. They decided to develop a new way of growing food in the city that could be scaled-up to fit diverse urban spaces from back yards to large buildings. Bristol Green Capital provided some vital start-up funding – but the duo are still looking for more investors to back their venture.

Peter and Dermot studied at Europe’s biggest aquaponic farm – Bioaqua – set up just for years ago in Somerset by ex-chef Antonio Paladino and partner Amanda Heron. Antonio travelled the world to research ancient farming methods and discovered the Mexican “Chinampas” or floating gardens – farming on rafts in lakes. This led to developing Bioaqua which incorporates trout and ducks in a symbiotic system. The farm produces large leaf vegetables as well as smoked trout and garlic, trout pate and raw honey. They also run aquaponics courses.

Grow Bristol are currently transforming a disused industrial site near Temple Meads into a productive farm with space for educating the public.

This is part of the Bristol Green Capital Urban Growing Trail in conjunction with partners Incredible Edible Bristol and Bee the Change see www.bristolgreencapital.org/projects/urban-growing-trail/. An old shipping container will house their optimised food production system. This literally came off the back of a lorry – an upcycled insulated delivery container. 

Grow Bristol feed the fish with locally sourced foods, including grain waste from Bristol breweries. The recycled container system aims to produce 40-50 kilos of fresh, sustainable, green leaf per week – year round. Longer term they plan to scale up to a larger growing space and grow 400-500 kilos weekly. 

A recent study by Sheffield University predicts most British soil has just 100 harvests left before it’s totally depleted. The fact that agriculture consumes a whopping 70 per cent of the water supply, while drought spreads across the world, is the definition of non-sustainable. Aquaponics closed loop system mimics nature and saves 90 per cent water compared to field crops. For once the answer does not lie in the soil – but in removing soil from the growing equation.

Grow Bristol: growbristol.co.uk | Baqua: baqua.org.uk | Urban Growing Trail: bristolgreencapital.org/projects/urban-growing-