FISH FARMING TECHNOLOGY
URBAN AQUAPONICS by Pete Whiting, Grow Bristol
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row Bristol is a small social enterprise with big plans for farming fish and greens using aquaponics. Set up by myself, with business partner, Dermot O’Reagan, Grow Bristol is transforming a disused space in the centre of the city of Bristol, UK, into a farm for the future. Our aim is to produce great food in the heart of the community where it is eaten, whilst farming in a more sustainable way. We hope to change the way we feed our city, using innovative agricultural methods and by connecting the people of Bristol to their food. At Grow Bristol, we believe in producing truly local, high quality food, close to the people who eat it. Currently, there is a need to explore further ways to grow more quality food, more sustainably, on less land, with fewer resources. Fisheries and farmland are increasingly coming under pressure. A recent report by the University of Sheffield created widespread speculation that there may be only 100 harvests left in UK soils due to intensive agriculture (we have reached Peak Soil as well as Peak Oil!) Water scarcity is also becoming a bigger problem globally and the UK is one of the largest importers of virtual water (other nations’ water used during the production of our imports). The food miles and carbon footprint of what we eat is also contributing significantly to climate change. Clearly, farmers need to continue to consider alternative methods of producing and transporting their food. Can one part of the solution be to produce more in the city for growing urban populations? At Grow Bristol, we initially began farming using a more conventional approach. We started by growing salad leaves in the soil in two large polytunnels, but were disillusioned with the vulnerabilities of the system and lack of suitability to the urban environment. We were producing on average 60kg (or 600 small bags) of mixed leaf salad a week for the local market. However, with a short growing season, a hugely inefficient irrigation system, poor soil and limited effective pest control, we started to consider the need for more resilient solutions. That’s when we turned to commercial urban aquaponics. Having visited Paignton Zoo’s ground breaking Verticrop hydropon-
ics system we were inspired to set up our own urban farm: producing vegetables vertically, without soil and using much, much less water! In this type of system, the water and nutrient solution is pumped around the suspended root zone of the crops on multiple layers, perhaps ten high. The water is then re-circulated rather than running to waste or evaporating. With ‘Controlled Environment Agriculture,’ almost everything can be managed to optimize growing conditions, even the light. Philips, one of the leading commercial producers of LED grow lights, are creating “Light Recipes” (with particular parts of the light spectrum) to manipulate productivity, nutrition, taste, and texture in crops, in the absence of daylight. It sounds futuristic, but such closed growing systems could potentially mean food security in the desert, in our cities, or even the arctic year round. Add to all this, the possibility of farming fish as well as growing greens and you have aquaponics. Integrating RAS aquaculture into
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