Had Heiko Hagdorn become a circus artist and the non-managing owner of what, by Dutch standards, might be considered a small yet globally esteemed greenhouse tomato production company with additional outdoor cultivation, he would have undoubtedly kept at least ten balls in the air, even when everyone else was juggling only eight or fewer.
Learn more about the Hagdorn family in a highly recommended five-part series available on ARD Mediathek
As if it were a matter of course, Hagdorn casually mentions that while we are still discussing the general market situation for vine, cocktail, and snack tomatoes, a heat pump the size of two shipping containers is currently being completed. He plans to use it to heat his six hectares of tomatoes in the future. In the medium term, he also envisions generating his own electricity with two wind turbines, which would make the CO2 footprint of his tomatoes almost negligible. This could even lead to expanding to a symmetrical 2 x 4 hectare greenhouse.
Before we look to the future, let’s go back to the beginning. While Hagdorn might have made a good circus artist in a figurative sense, but constantly traveling the world would have been difficult for him. He’s the kind of person who prefers to stay close to where he grew up. He illustrates this with an example: When it became increasingly clear around the turn of the millennium that further expanding outdoor vegetable production north of Stuttgart was impossible due to limited land and irrigation, he was offered a plot of land for greenhouse production. Although the area wasn’t too far from his hometown, the distance was enough to dissuade him from pursuing the offer.
In 2008, the Hagdorn family constructed their first four hectares of greenhouses, followed by an additional two hectares for winter tomato cultivation in 2016—and 2024 is still unfolding...
Hagdorn can rightfully market his tomatoes under the slogan "Our Homeland – Real & Good." He grew up alongside his wife, Karin, who now ensures that the company’s finances are in order and that everyone has a home and regular pay. His operations manager is the sister of a childhood friend from kindergarten. Even the heat pump was not designed or built far away, but came from the neighboring village. Many of the Turkish-origin women who work in his greenhouses once worked for his father in the fields, and Hagdorn himself went to school with their children. His own five children are also deeply rooted in the community, participating in sports clubs, music, and the local fire service.
In the real estate market between Heilbronn and Tuttlingen, having strong local ties is essential to acquiring enough land for projects like constructing a four-hectare greenhouse with irrigation ponds, offices, social rooms, and a sorting and packaging facility. By 2007, the timing was right, and in 2009, Hagdorn planted his first tomatoes. Almost from the beginning, crop consultant John Hendrix has been guiding the success of the tomatoes in Hochdorf an der Enz. At the time, 5.7-meter-high walls, clear glass, a double shading system with Svensson screens, and well-sized cogeneration plants were state-of-the-art.
Together with Hendrix, Hagdorn first optimized the climate control in the greenhouse. They replaced the cross-fans under the gutters with ClimaFlow fans above the crops, which resulted in a much more uniform climate. Hagdorn also noticed that the plants became less vegetative as the heat was pushed downwards, keeping the plants more open and allowing more light to reach the crops. The improved air movement reduced condensation on the stems, effectively eliminating botrytis issues. Additionally, energy savings were an added bonus.
Even outside the farm shop's opening hours, Hagdorn's delicious tomatoes are available on-site from the vending machine, 24/7.
In the years that followed, several factors aligned. Hagdorn wanted to keep "his people" employed year-round, he had a growing interest in "the subject of lighting," and his tomato buyer was eager to offer regional produce during the winter months. This led to the development of a plan for winter tomato cultivation under artificial lighting. Once the terms for acquiring the neighboring plot were adjusted to everyone’s satisfaction, construction of the new greenhouse began in 2015. By then, the Hagdorns had gained significant experience with greenhouse cultivation, particularly of tomatoes, so they took the planning of their winter tomato greenhouse into their own hands—despite winter cultivation being, as they say up north, a completely different ballgame.
Convincing the tomatoes, with their delayed seasonal growth, to not only grow taller but also bear fruit introduces a series of new challenges. For example, when plants are exposed to 16 hours of light during winter, they require frequent watering, which quickly leads to high humidity levels. There are complex, high-investment technical solutions for managing this, but there are also simpler, more cost-effective options.
Hagdorn chose the latter and has successfully controlled humidity for the past three years using fans installed on the external gables. These fans blow comparatively dry outside air into air hoses beneath the gutters via a heating register, allowing him to avoid the use of fungicides. During the planning phase for the greenhouse, LED lighting was still prohibitively expensive, so high-pressure sodium vapor lamps were initially used, despite their heat-related issues. However, during the construction phase, LED prices suddenly dropped to a quarter of their original cost. With rising electricity rates, Hagdorn switched to LED top lights and row lighting after just five years, incorporating them into the two-hectare greenhouse.
Normally, thanks to the light-blocking Obscura screen, the bluish-red, northern-lights-like glow from the LEDs is barely visible from the outside at night. However, this past winter, images of an unusually illuminated night sky circulated on social media. Hagdorn recalls that the likely cause was an overly sensitive fire alarm. Since screens are programmed to open in the event of a fire, the climate computer followed protocol, treating the surrounding towns to an unexpected light show.
