Gemüsebau Steiner and the Bavarian REWE supermarkets have been linked by an exclusive partnership for ten years. With the energy and lighting concept of their greenhouses, they are regarded as a model company throughout Europe.
one: At the REWE Group stand at the Green Week, your concept was presented as groundbreaking for the entire industry. What makes your greenhouses so special?
Wolfgang Steiner
Wolfgang Steiner: 95 per cent of our greenhouses are heated by geothermal energy from the neighbouring geothermal plant and the return flow from the Kirchweidach district heating network. This is a reliable and constant source of heat, regardless of wind and weather all year round. The remaining five per cent is obtained from the waste heat of a nearby biogas plant. With the help of a heat storage tank, the heat can be utilised as required. The photovoltaic system on the roof of the production halls supplies the greenhouses with electricity.
Florian Steiner: " We do without chemical plant protection, rely exclusively on beneficial organisms and use biodegradable strings. We collect rainwater and condensation water from the greenhouses in a large basin and therefore have a self-sufficient water balance. We therefore use neither CO₂ for the heat supply nor precious drinking water for irrigation. We have short transport routes to the REWE and PENNY warehouses. This means that our production is regional, resource-saving and environmentally friendly. This sustainable concept makes us unique in Germany.
Wolfgang and Florian Steiner, managing directors of Gemüsebau Steiner and BIOhof Kirchweidach
one: In 2018, you also decided to grow organic produce. What is the difference in cultivation?
BIOhof Kirchweidach was also created in cooperation with REWE, as there was a high demand for regional organic products. In conventional cultivation, our plants grow on a coconut substrate, a waste product from coconut production. The organic plants grow in nutrient-rich topsoil and are fertilised with home-made compost made from our plant residues. This results in a wonderful nutrient cycle.
one: In 2020, you put the first greenhouse in Germany with 100 per cent LED lighting into operation in Emmerting. What are the advantages?
Wolfgang Steiner: This allows us to compensate for the fewer hours of sunshine in winter, achieve a longer, more intensive ripening period and can also offer ripe, sweet tomatoes from the region in winter. We save 38 per cent energy compared to the previous lamps. The municipality of Emmerting also benefits from the new lighting technology: the heat pipe to the greenhouse means that many households can be supplied with environmentally friendly district heating at low cost.
one: Your company always attracts a lot of media interest, and in 2023 you won the Sustainability Impact Award. What is your success based on?
Florian Steiner: This award makes us very proud as it recognises our commitment to Sustainability. And we are actually still a newcomer, our company has only been in existence for just under ten years! But it's a well-rounded concept, from the sustainable energy source and natural crop protection to the good partnership on an equal footing with REWE.
Wolfgang Steiner: Product quality also contributes to our success. Every day on the plant counts - our fruit is harvested when fully ripe. Flavour is our top priority, even before Sustainability. We have to impress our customers with this.
one: What projects are you working on in 2024?
Wolfgang Steiner : We have now drilled our own geothermal well, which we can use to supply ourselves with district heating. This will be put into operation in the autumn. We are thus also setting up a district heating concept for the entire region. We would also like to add other products to our range.
