Vertical farming / city farm © TU Berlin
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This summer, water shortage is topical again in Germany. Politicians have already hinted that in order to safeguard the supply of drinking water if the drought persists, it might be forbidden in the future to water your own garden. However, the amount of water used in our gardens is not so significant. Worldwide, agriculture consumes around 70 percent of all drinking water supplies.

Students at TU Berlin are now researching a new hydroponics method that can help conserve water in this sector. In hydroponics, plants are grown without soil and exclusively in an aqueous nutrient solution. In contrast to conventional hydroponic systems, the Berlin students rely on treated recycled water for their vertical hydroponics farm ‘Shower-Tower 61’ which is housed in the ‘Beach 61’ beach volleyball facility at Gleisdreieck Park.

Cooperation with water treatment plant

In this vertical hydroponic farm not far from Berlin’s Potsdamer Platz, the treated water is used for food production. The farm, which was built in cooperation with a local water treatment plant, consists of eight two-meter-high white square columns, which are mounted directly on the back wall of the showers at the volleyball court.

The “Reallabor Mobile Blue Green Infrastructure” was built together with students from the “Roof Water-Farm TU project” workshop led by Dr. Grit Bürgow, student coordinator Andreas Horn and architecture student Gabriel Sigler. The aim is to explore “how the role of gardens and parks for the urban climate, biodiversity and people’s quality of life can be integrated into political decisions to ensure more sustainable management of urban areas.”

There are 16 plant tubes where the mesh pots with the plants are placed in each one. “The treated and nutrient-enriched shower water drips into the tubes from above and waters the roots protruding from them,” the students explain. “This provides the plants with water and nutrients.” The vertical hydroponic farm is suitable for growing salad varieties, herbs such as basil, cabbages such as bak choi and red kale, beets such as chard as well as edible flowers.

Water treatment system © TU Berlin

Hardly any space required

With their project, the researchers want to answer four important questions. “First of all, is it even possible to treat shower water with existing technologies so that it can be used for producing food that is completely safe for consumption,” says Grit Bürgow. The water used for food production must meet the DIN standard for irrigation water.

The second question that needs answering is whether such a vertical hydroponic farm is suitable for local commercial and non-commercial food production in an urban environment like Berlin. “Thirdly, is it possible to eventually involve the population in this kind of project with the aim of ensuring that such blue-green infrastructures are operated and used by local residents themselves in the future? Fourthly: What effects does such a hydroponic farm that is combined with reed raised beds (which allow for evaporation) have on the urban microclimate?”

The major advantage of this type of vertical farm is that it does not take up much space in urban areas, which are both scarce and expensive. It can also be installed on facades and the walls of houses. Just like the ‘Shower-Towers 61’ on the back wall of the showers. “This is really efficient,” says Grit Bürgow.

Is there the will to grow food this way?

Given that their farm is actually a laboratory and that the research is carried out directly in an urban area, they are also in close contact with the operators of ‘Beach 61’, the scientists point out. “This interaction is important in order to find out if people are willing to accept these innovative ideas. For example, is the operator of the beach club interested in using the lettuce and herbs in their beach bar? Is it realistic to imagine that they might operate a farm like this with us or even on their own after the end of the actual laboratory research?” The added value is clear: short transport routes and dewy fresh herbs.

Read more IO articles on hydroponics via this link and on sustainable food production here.