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Digging for self-sufficiency 2.0

 Surprise - Switzerland 10 October 2019

At the Zurich headquarters of UrbanFarmers, economists and scientists have joined forces to bring agriculture into cities. They are convinced that they have found the solution to one of humanity’s greatest problems. (1720 Words) - By Florian Blumer


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Christian Bärtsch in der UrbanFarmers Box (Portraitausschnitt. Downloaden, um die gesamte Aufnahme anzusehen).Photo: Sophie Stieger

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System Malthus (Portraitausschnitt. Downloaden, um die gesamte Aufnahme anzusehen).Photo: ZVG/Sophie Stieger

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Jungfischaufzucht für Aquaponics.Photo: ZHAW/Sophie Stieger

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Salat in der UrbanFarmers Box, aus dem Wasser gehoben (Portraitausschnitt. Downloaden, um die gesamte Aufnahme anzusehen).Photo: Sophie Stieger

We are standing inside a greenhouse in a disused shipping container in the middle of Zurich, and we are sweating. In front of us the Prime Tower is beaming in the sunshine, to our left locomotives and freight trains are chuntering past. "Kunst & Kommerz" (Art and Commerce) starts right behind us in the middle of the hip and urban realm of the Viaduktbogen - along with the new shops and offices that have sprung up in the viaduct arches of the railway. UrbanFarmers, the team who runs the greenhouse container, have moved in here too. Their business is still in its infancy, but they have big things in mind.

The system the UrbanFarmers box uses is called aquaponics. Christian Bärtsch tells us how. The 21-year-old studied at the University of St. Gallen and has been on board with UrbanFarmers since its inception. At the moment he is working full-time with the business on an unpaid internship. The budding economist from the elite university talks to us this morning enthusiastically about fish farming and growing plants in an environmentally friendly way.

Food from the car park

Aquaponics may sound high-tech, but it is in fact very simple: fish excrete nutrients, particularly through breathing - these are used by crop plants, whose roots are underwater, as a natural fertiliser. In return, the plants clean the fishes' water. This natural cycle doesn't just make the use of chemical fertilisers unnecessary in conventional hors-sol production, but it also saves by way of contrast up to 80 to 90 per cent of water. The only things those who operate the unit have to do are take care of the fish food, the energy for the water pumps and the thermal heat in the winter. In return they get fish, cabbages, salad and vegetables on their plate from the back yard. All this without needing farm land which, worldwide, is becoming ever more scarce. A terrace, a large car park or urban areas that are lying fallow are all that you need. Such places are abundant in cities: for example, it is said by Andreas Graber, co-founder and technical leader of UrbanFarmers, that there are enough suitable spaces in Basle for up to a quarter of the population's needs for fresh vegetables and fish to be met.

According to Bärtsch, the Aztecs already knew of and were making use of the symbiosis between fish and plants that grow underwater. In North America, aquaponics units have been on the rise since the early 1990s. It has caught on in New York, for example, in a big way. Aquaponics is a part of the "urban gardening" movement: in large cities like San Francisco, Detroit, or Toronto chickens are kept and vegetables are grown on peoples' roofs, in their front gardens, and on other uncultivated land. Since the beginning of this year, UrbanFarmers has been the first business to offer aquaponics in Europe too - for that they won the new award for sustainability in Switzerland, the "Prix Nature". What's more, Bärtsch is of the view that the concept is firmly rooted in Swiss history. During the Anbauschlacht, the drive to increase food production during the Second World War in order to decrease Switzerland's reliance on food imports, under the banner of self-sufficiency the cities were also cultivated as much as possible, Bärtsch states.  The young man from Winterthur says that he feels part of a large, international movement, which together pursues the same ends but through different means. People want to know where their food comes from once again. Ever more young city-dwellers in developed countries have had enough of being at the mercy of one food scandal after another, and of feeling like they are being fed by a food industry which makes products under conditions which are harmful to humans, animals and the environment, and which are then transported halfway around the world for good measure.

Killing fish, not veganism

Is aquaponics the solution to the food security problems of a rapidly growing world population that is moving to cities in ever-larger numbers? The idea may sound captivating, and the aims are noble. But will it actually work? Interest and curiosity are huge - all the largest German-language media outlets, from the news magazine "Der Spiegel" to "Zeit Online" to the state-owned German television channel ZDF have reported on the young Zurich native's idea unwaveringly positively and enthusiastically. But some of UrbanFarmers' potential customers are also somewhat sceptical: the fish basin, which takes up around a fifth of the container's surface area seems rather small for the many fish to fit inside, and the hors-sol cultivation of plants gives rise to fundamental doubts. Andreas Graber doesn't try to sugarcoat things at all. He knows exactly what he's talking about too: he's worked in aquaponics for ten years as a scientist at the ZHAW University of Applied Sciences in Wädenswil, and his specialism is fish and aquatic ecology. On the critical question as to whether fish farming is animal-friendly, he answers with this observation: "the concept of species-appropriate farming of animals is actually a contradiction in itself". He compares fish farming with the farming of pigs: "if you raise pigs in a shed, of course it's not the same as if you hunt wild boar in a forest".

Graber is pragmatic. He doesn't want to dissuade anybody from eating meat. But he does want to make people think about what they're doing: "as an Urban Farmer, you must be prepared to kill a fish", he says. Vegans are, according to Bärtsch, split as to whether vegetables produced using aquaponics are vegan or not. To which Graber says merely: "we offer a technical approach towards concrete problems. We don't promise heaven on Earth. Harvesting, or for that matter dying, is a part of the natural cycle of life."

Organic urban farming?

However, the wellbeing of the fish is fundamental to the running of things here: if they are stressed out, then they start to attack each other, eat little, and produce less fertiliser - which in turn has a negative effect on the growth of the plants. In the initial stages it was shown that, rather than too many fish swimming in the rather small pools, in fact too few were doing so.  The tilapias did not form a school of fish, but rather began to defend their own territory. Therefore nutrients for the tomatoes, heads of lettuce and the basil above them became scarce.

Environmental and sustainability concerns are very important to the UrbanFarmers. Therefore crop spraying is not done with poison but by using beneficial organisms, and they work on energy efficiency so that one day the unit can be powered by solar energy. UrbanFarmers is not certified organic. Andreas Graber says that aquaponics works outside established parameters: "we are taking farming out of the country and practicing it in the city and on roofs". Sabine Lubow from Bio Suisse, the umbrella association of more than 30 organic farming organizations and 6300 farms engaging in organic production in Switzerland, says this is all still very new. But she also adds: "essentially there is no reason why we wouldn't give them certification, we are open to the idea and ready to give it careful consideration." In turn, Graber was pleased at this spirit of co-operation and claimed that he would like to link up with them.

Not child's play

In the greenhouse it's getting warmer and warmer, and a ZHAW student is hard at work tending to the plants. She is writing her bachelor's thesis on the UrbanFarmers box and is working on improving the quality of the cultivated plants. It quickly becomes clear that an aquaponics system like this requires work. About half an hour a day, Graber says. They are targeting city-dwellers living on a housing co-operative who can operate a unit like this. However, the question is often asked: how realistic is it that teachers or architects without farming experience can successfully farm fish and cultivate plants long-term?

Both Bärtsch and Graber confirm that a certain amount of know-how is needed.  This is even truer when operating a larger unit that can be installed on flat roofs. It is here that the UrbanFarmers see the greatest potential. As operators of they are already thinking about restaurants or canteens there, for instance. "A rooftop farm always needs professional people to run it, trained horticulturalists and fish farmers, who are responsible for the most important operations. Other work can be carried out by guided non-specialists", Graber says. "But we also seek to educate those people who are interested so that we can enable them to make their own simple unit".

A box has already been sold at a cultural centre in Berlin dedicated to sustainability. UrbanFarmers are also in negotiations with other interested parties. The boxes are an ideal investment - a ready to use container unit, delivered, costs around $50,000. They don't exactly pay for themselves. But those who are purely interested in the money should go and buy their fish and vegetables in the supermarket. With rooftop farms things are quite different:  larger sites can be quite financially worthwhile.

With others or home alone


The UrbanFarmers see another, more social, use for the smaller sites. They claim that aquaponics is an opportunity to encourage living together in anonymous big cities. Alongside working together on the container farm, it could also be possible to set up a barbecue in the corner - the green container can thus be seen as an oasis in the concrete desert.  Likewise, schoolchildren can see close-up how their food comes into being. This pedagogical aspect is also emphasized by the designer Anotnio Scarponi, who in collaboration with Graber has developed a prototype of a home unit. Under the slogan of "one meal a day" everyone can, after they've been shown how, farm fish and grow cabbages themselves. All that is needed is a bit of money and space. Costs for materials, according to Scarponi, run to around $16,000-$21,000. The unit is about as large as two refrigerators and can contain about as much water as a bathtub. The in-home aquaponics unit, named "Malthus", is still being developed but a prototype is already in progress. Whoever wants to try their hand at building cities anew, can also practice a food revolution out in their own kitchen first.

Translated into English by Benjamin Dennis

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