Frequently Asked Questions

Unit 84 is currently closed as we are relocating the farm. Please see our blog for more news about our plans.


Who are GrowUp Urban Farms?

GrowUp Urban Farms is a London business focused on industrial-scale Controlled Environment Production (CEP) farms, that produce the highest quality fresh produce and freshwater fish.

Why did you start the business?

We want to change the production and distribution of nutritious food to make it more local and more sustainable. We aim to reduce the environmental impact of agriculture and employ local people so communities can be more self-sustaining – something that will become increasingly important as our climate changes and our cities expand.

Where can I buy your produce?

Whilst we're relocating our farming system, we don't have any active production, so we're not selling any produce - check out our blog for more details on our current projects.

What are the environmental and social benefits of Controlled Environment Production for local communities?

The environmental benefits of our farms include reducing waste products from agricultural production and making use of previously unused urban brownfield sites. We can reduce the environmental impact and cost of transportation and packaging by selling and delivering to local customers.

A more local supply chain gives communities a chance to make informed decisions about the way their food is grown. Our food is fresher (as we deliver locally), grown more sustainably, doesn’t use harmful fertilizers or chemicals and is more consistently priced regardless of the season.

We are building expertise in aquaponic vertical farming and raising awareness about the way food is grown for people living in cities. Through the GrowUp Box, we have already reached a wide range of audiences, including schoolchildren and hobby aquaponicists. The GrowUp Box also hosts events for specialist groups such as universities and community groups.

Our aspiration is to employ and train local young people who may have dropped out of formal education or been unable to find employment, and provide them with the skills, experience and confidence to work in Controlled Environment Production or develop transferable skills to help them move into the area they want to work in. The more farms we build, the more people we can employ, and the more communities in which we can have a positive impact.

Why do you want to grow food more locally?

By reducing the distance from farm to fridge we reduce the amount of greenhouse gases associated with the processes of refrigerating, storing and transporting food.

With growing urban populations, innovation in agriculture is necessary if we are to develop a socially and environmentally sustainable means of feeding people who don't have access to the space, or the desire to, grow their own food.

GrowUp Urban Farms aims to address some of the fundamental flaws in our global agricultural system by using aquaponic and vertical growing techniques to build farms closer to consumers.

We produce greens and fish that are sustainably grown for a local market – reconnecting people with the way food is produced and what it takes to produce it. This reconnection can help people to make an informed choice about the food they eat. With growing awareness and demand for ethically produced food, we’re pioneering innovation in food production for the cities of the future.

Are you currently hiring or taking on any new volunteers?

We’re chuffed that you find what we do so inspiring and interesting! Our aspiration is to employ local young people who may have dropped out of formal education or been unable to find employment, and provide them with skills, experience and confidence. Check out our vancanies page as any future opportunities will be posted here first.

If you share our passion for changing the way we feed people in cities, you may be interested in volunteering at The GrowUp Box, run by our sister organisaion GrowUp Community Farms.

I love aquaponics! How can I find out more about setting up my own aquaponics system?

We know lots of you are really interested in finding out more about aquaponics. If you’re in London or in the UK, you can find out here about open days The GrowUp Box, and what courses are running soon.

You can also contact the British Aquaponics Association (BAQUA) for more information about aquaponics in the UK.

We also recommend the Upstart University website where you’ll find a number of podcasts and tutorials all about aquaponics and setting up your own system.

Is your food organic?

Under current EU regulations, only plants grown in soil, in the ground, can be certified as organic. We grow without any chemical pesticides or fertilizers but our produce can’t currently be certified as organic in the UK.

Does your salad taste like fish poo?

No, it tastes great (although we have to admit, we’ve never eaten fish poo). Since the roots of the plants absorb the nutrients from the water, the leaves (the bit we eat) are clean, healthy and don’t sit in the water. Fish poo contains high amounts of ammonia and other nutrients that act as great fertilisers. The solid waste (fish poo) is removed from the system through the filtration system leaving just the nutrients in the water for the plants to feed on. As the plants take up the nutrients their roots act as filters re-circulating the clean water back into the tank. Animal poo (including human) has been used as a fertiliser in farming since the dawn of time, ours just happens to come from fish.

Are there any issues with diseases in the water?

Fish health is key to the success of an aquaponics system. The main cause of fish disease in aquaponics and aquaculture comes from overcrowded tanks and unclean water. To maintain the health and high welfare of our fish we do the following:

  • We don’t overcrowd our tank – ensuring our fish have enough space is the first step to controlling disease.
  • We monitor fish behaviour – you can tell a lot about the health of a fish by the way they behave.
  • We check for any odd spots on the fish or in their discharge – these can often be the first signs of disease.
  • We check water quality – making sure the water temperature and pH are at optimum levels is key to maintaining a healthy population of fish.
  • We source fish fingerlings from CEFAS-certified suppliers only – this minimises the risk of diseases being introduced into the system.

Are Tilapia the best type of fish to use in aquaponics and what else do you grow?

Tilapia are ubiquitously farmed across the world and they are well-trialled in aquaponic farming systems. They’re a hardy fish and prefer to live in larger groups, making them ideal to farm at a slightly higher density than other fresh-water fish. They are also omnivorous, which means they can be fed on high-protein food that isn’t made from fish-meal and fish-oil. Whilst we currently use an industry-standard fish food, we’re exploring options for fish-meal free fish food, a key part to creating a more sustainable food loop for aquaculture.

How do you make sure the fish are farmed ethically?

Animal welfare is extremely important to us and we believe it to be key to the success of commercial aquaponic farming. We regulate and monitor a number of conditions on our farms including:

  • The water temperature.
  • The chemical composition of the water.
  • The amount of food we give the fish.
  • Light levels; And oxygen levels

We also make sure to optimise the stocking density of our tanks so that the fish are healthy and happy – rather than stocking them as densely as possible. Tilapia like to live in large groups. This means that they can live in quite high densities, but we are also careful not to overcrowd the tanks. When it is time to harvest the fish, we do this humanely.

How do you kill the fish?

We take the welfare of our fish very seriously – and this includes being open and transparent about how we kill the fish.

When the fish are ready for harvesting, they are taken out of the main tank and put into a smaller container. By running an electrical current through the water in this tank we can stun the fish so that they are immediately rendered unconscious. By passing a second, longer current through the water the fish are then killed. This also keeps the stress levels in the fish population lower, which is better for them and makes them taste better.

Can you grow root vegetables using aquaponics?

Technically it is possible to grow vegetables like carrots and potatoes in an aquaponic system – but we choose to grow green leafy salads and herbs for a number of reasons:

  • If you wanted to grow root vegetables you’d probably need to use aeroponics (using a water mist, rather than a nutrient solution to feed the plants) which isn't our area of expertise.
  • Aquaponics is very well suited to leafy green plants because the waste from the fish is so nitrogen-rich. We want to minimise any additional nutrients we have to add for the plants and make the most of our natural source of fertilizer.
  • Salads and herbs are high-value perishable crops, and it makes sense to grow them as close as possible to the people who are going to eat them.

How do you know how many fish you need to produce the right amount fertilizer for the plants?

Aquaponics relies on keeping a careful balance of nutrients and chemicals in the water so that both the plants and the fish are healthy. We can calculate how much waste the fish will produce by measuring how much food we give them, and understanding the chemical content of that food. We can then adjust the amount of food we feed the fish so that there are always enough nutrients for the plants.

What do you feed the fish?

We feed our fish on an industry-standard fish food, which includes fish-meal and fish-oil from wild-caught fish. We think aquaponics has the opportunity to break the unsustainably reliance of aquaculture on wild-caught fish or soya. We’re exploring alternative food sources including algae and insects for Tilapia.

Do plants grow faster in aquaponics than in soil?

We farm in a controlled growing environment — this means we control the amount of water and nutrients that reach our plants, and we have a growing cycle (the length of time it takes to go from seed to harvest) of around 2 weeks (and this varies depending on the type of plant). This is partly because our plants get the nutrients they need directly to their roots, and partly because we’re growing crops that are well suited to the nutrients in fish waste. Using LED lighting tmeans we can grow year-round (traditional farming can't grow salads in the UK between October and February). This means that over the course of a year, Controlled Environment Production aquaponics can be much more productive than traditional soil-based farming.

Can I come and visit GrowUp to film/photograph the farm?

Unit 84 is now closed as we are relocating the farm. Check out our blog for more information.