Scherzer Gemüse can harvest up to 40,000 heads of lettuce a day at its hydroponic facility in Dinkelsbühl, Germany. "Currently, we only produce lettuce, but in the summer, we had some rocket salad," owner Andreas Scherzer explained. "We market the lettuce throughout the year and sell it mainly to food retailers but also to individual wholesale markets.
"Sales are primarily in southern Germany. The lettuces grow in bales and end up on sale that way. This means that the product remains fresh for consumers for much longer. This is also one of the most unbeatable arguments for hydroponic cultivation," he continued.
The new facility was not commissioned until the end of 2021 and has a production area of 5 hectares. Scherzer Gemüse's broad-based customer base includes food retailers as its main customers. "We have been in production with the new building for a year. The seeded gutters automatically go into the germination chamber, which is located below the system. Once the seed has germinated, it comes up from the germination chamber to continue growing." Scherzer estimates demand for the lettuces has been good, although there have been isolated weaker weeks. "My guess is that interest in this will increase over time," he said.
In principle, harvesting still takes place by hand. However, not many forces are needed in the greenhouse anymore, he said. "Especially in the packaging area, we still need a lot of labour. In contrast to outdoor cultivation, we are not affected by extreme weather such as heat, cold, and rain, which is, of course, much more pleasant for the employees. Outdoor cultivation certainly still has its raison d'être. But in the future, such concepts will certainly come more and more, especially when you look at the issues of water supply, fertilisation, pesticides," Scherzer says.
At the cutting edge of greenhouse technology
"Production takes place relatively independent of the weather outside, but what's happening outside still affects cultivation. However, temperatures can be regulated inside the greenhouse. As far as greenhouse technology goes, we're on the cutting edge."
The plant was commissioned at the beginning of October 2021 so that the first lettuces could already be harvested in November of the same year. "In the past, of course, we were involved in outdoor cultivation, but then we increasingly focused on greenhouse cultivation. In 2020, we agreed to invest more in the production of hydrosalads. On the one hand, this allowed us to expand our range, and on the other hand, there are also great advantages from a cultivation point of view," Scherzer says. The company is also known for its greenhouse tomatoes.
The advantages he mentions include the continuous availability of produce, which is of particular interest to end customers who prefer regional products above all. "Apart from that, we also have lower water and nutrient consumption and higher land efficiency due to our clearly regulated system. Each plant has the ideal space it needs." Furthermore, in protected cultivation, he said, there are also no problems with aphids and other complications found in the open field.
The water used for irrigation consists of 95 percent of the company's own stock of rainwater, which was collected via the rooftops, controlled in the system, and adjusted according to specific values. "Thanks to our large rainwater basin, we can collect and store enough water in rainy months and then use it accordingly in drier months."
"The big silos contain fresh water. In the basement is the irrigation water system, which measures the water and pumps it on," Scherzer explains.
The plants are irradiated with a red-blue color spectrum via LED lamps. This makes the plant energy-efficient and ensures consistent quality of the plants, he said. "The plant is darkened on the outside via blackout screens because otherwise, you would see the light for miles." The temperatures can be controlled remotely.
The lettuce production employs 45 to 50 people, most of them from Romania, who work at the plant throughout the year. "This is where the produce is packed, labelled, and loaded into the trucks. Thanks to the root bale, the lettuce stays fresh for a long time, so all in all, consumers get more out of the produce."