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Urban farming – the Swiss way

Smoked trout and crispy salad vegetables sourced directly from a producer just around the corner – nothing new for country dwellers but an entirely novel experience for their city cousins. This is precisely what is happening in the city of Basel thanks to Zurich-based company "UrbanFarmers". Founders, Roman Gaus and Andreas Graber have developed a system that combines traditional urban agricultural methods with aquaponics technology. The idea took shape during their time at the Zurich University of Applied Sciences in Wädenswil.

Roman Gaus and Andreas Graber may now be serious businessmen but they have lost none of the youthful enthusiasm and drive they showed during their student days. Together they founded the spin-off "UrbanFarmers", which has its headquarters in Zurich. Their mission is to transform urban wastelands (incl. flat roofs) from a concrete jungle into small-scale agricultural oases. Although urban farming and urban gardening have been around for quite some time (the US, in particular, has a sizeable urban farming community), what makes this project unique and unmistakably Swiss is the marriage of age-old techniques with cutting-edge technology (aquaponics). In Switzerland the names of Gaus and Grauber are on everyone’s lips thanks to their ingenious idea.

Fish and vegetables from a Basel rooftop

In summer 2012 Swiss UrbanFarmers opened Europe’s first-ever rooftop farm in Basel. The site for this pilot facility is the top of a former engine shed ("LokDepot") in the city’s Dreispitz quarter. Here, the natural symbiotic relationship between fish and plants is exploited to the maximum, yielding up to five tonnes of vegetables and 800 kilos of fish.

All is not quite what it seems… The "LokDepot" rooftop farm, Dreispitz, Basel. (in new window)

All is not quite what it seems… The "LokDepot" rooftop farm, Dreispitz, Basel.© UrbanFarmers.com

City-grown tomatoes and lettuces are particularly popular. In Wädenswil, researchers are looking into the possibility of using this system to  grow exotic fruits, as well as lemongrass. (in new window)

City-grown tomatoes and lettuces are particularly popular. In Wädenswil, researchers are looking into the possibility of using this system to grow exotic fruits, as well as lemongrass.© UrbanFarmers.com

How aquaponics works

The rooftop farm in Basel, which was set up by Swiss UrbanFarmers, is built around the system of aquaponics. The fish farm at the rear of the greenhouse provides the other sections with water and natural fertilisers. This means that the plants can be grown without humus and with 80% to 90% less water than traditional agricultural methods. This system is therefore a combination of two classic production methods: "aquaculture" (breeding fish and growing plants in water) and "hydroponics" (growing plants in water rather than in the soil).

The advantage of this closed loop system is that it does away with chemical fertilisers, pesticides or fungicides. In addition, the fish farm is antibiotics-free because population numbers are kept low and only fresh water is used.

Aquaponics – naturally simple. Vegetables and fish grow in a closed system developed by Zurich University of Applied Sciences in Wädenswil. (in new window)

Aquaponics – naturally simple. Vegetables and fish grow in a closed system developed by Zurich University of Applied Sciences in Wädenswil. © UrbanFarmers.com

Since 1994 the Institute of Natural Resource Sciences (IUNR) of the Zurich University of Applied Sciences Wädenswil (ZHAW) has been involved in pioneering research into aquaponics. Today, co-founder of the UrbanFarmers company, Andreas Graber, lectures in aquaponics at his alma mater and is considered a leading expert in the field.

Locally farmed fish on the menu in local restaurants

The Dreispitz rooftop farm is the first of its kind in the world. With financial support from the Basel-based Christoph Merian Foundation and the Federal Commission for Technology and Innovation (CTI), UrbanFarmers were able to plough a total of CHF 800,000 into this ground-breaking project.

As a "proof of concept" facility, the "LokDepot" farm should demonstrate the commercial and scientific feasibility of producing fish and vegetables in a closed water cycle. In the future, new urban agriculture projects will be able to benefit from the experience and know-how generated by this pioneering farm.

The farm supplies fish and vegetables to local restaurants. True to its green credentials, the farm delivers its produce by electric bike.

Short Q&A with UrbanFarmer Roman Gaus:

What contribution do you think the project has made to technological developments in general (green tech and cleantech)?

"In my opinion, this approach to urban food production is not only highly integrated, but also scalable and commercial."

"I think that the urban environment offers a great many synergies which are ripe for exploitation, such as the recovery of low-temperature waste heat and greenhouses powered by solar energy."

How do you see its commercial future?

"Commercial food producers and retail chains could integrate and sell UrbanFarmers’ produce in their own product cycles."