On their StadtFarm, the Berlin-based startup TopFarmers GmbH produces sustainable and locally produced fresh food, which is distributed via a farm store and delivery service. Top Farmers was one of nine finalists of the Next Economy Awards 2020.

Since 2017, TopFarmers have been operating Europe's largest glass aquaponic farm in Berlin. 50 tons of African catfish and 30 tons of vegetables and fruits are produced there every year. Compared to conventional agriculture, 80 percent of the land and water consumption and 92 percent of the CO2 emissions are being saved.

StadtFarm grows fish, vegetables, and tropical fruits in a closed circulation system. The water from the fish tanks is transferred to filter basins. In these basins, bacteria convert the ammonium from the fish excrements to nitrate, which the plants can use to grow. Then the water flows through a worm filter with earthworms and bio-filters with billions and trillions of bacteria. Plants growing in a specially formulated ‘terra’ absorb the nutrients and, thereby, clean the water which then is returned to the fish tanks.

The work of StadtFarm mainly contributes to the Sustainable Development Goals 2, 3, 11, 12, 13, 14, and 15: