"NL: "Cultivation on water is now really starting"

Cultivation on water exists. Jan Botman: "The technique of cultivation on water seized me years ago and it has not let go of me. I have worked as an exporter of vegetables for about twenty years, particularly in the overseas market. In the end, I wanted to do something else. I read about the program ‘Cultivation Out of the Soil’ from Wageningen UR. Within this program, cultivation systems for open field horticulture are developed that meet European regulations for water quality, among others in collaboration with Proeftuin Zwaagdijk. Back then, I had already visited a project for cultivation on water by means of gutters in Belgium several times. I contacted Wageningen and got on board as an entrepreneur. In the meantime, I was already involved in a program of leek on water at the experimental company of Practical research Plant & Environment in Vredepeel. In the end, I started to work seriously on it in 2012."

"Proeftuin Zwaagdijk conducts executive research and I developed the Botman Hydroponics system: a good combination. The nice thing is that the continued development of the system runs parallel with the tests that are being done. Many other systems of cultivation on water work with styrofoam, for example. I absolutely wanted the materials of my system to be 100% food safe and that is why I opted for plastic. In 2013 I made the first model of the Botman Floating Tray, to be used for both leaf crops and ornamentals. After several years of trials and research, we gained more deeper insight into how the system works and how crops can grow optimally. The nice thing about plastic is that it conducts the temperature: it has no insulating property. Contrary to what is sometimes thought, this just offers great advantages. The water on which the tray floats can thus function as a form of underfloor heating – or even as cooling. This allows us to create a sub-climate at crop level, without having to get a certain temperature in the entire room: that’s very sustainable. Through this system there are no remainders left at all. The plastic can be recycled and the cups in which the plants are propagated, are biodegradable. All parts have been thought through to the last detail in order to achieve the most efficient result possible."

"Another thing that was assumed for a long time, is the idea that the amount of oxygen in the water was not really important: the opposite is true. The presence of oxygen is definitely very important for the absorption of nutrients by the crop. That is why I also developed a system for this, which has been researched for three years now. All results so far indicate that we have taken the right direction. Moreover, in low-oxygen water pathogens are much more likely to strike and that is one of the biggest risks of cultivation on water: if things go wrong, such a bacterium certainly will spread rapidly through the water. So you have to make sure that it cannot go wrong. That works now without problems. The next step is to control the water temperature electrically via a heat pump for both heating and cooling. In the meantime I have been working on it for ten years, but I feel that it will only take off now. The real production is going to be started, I'm really looking forward to that. Yes, it takes an enormous amount of time and attention to think out every step. I get up with it and I go to bed with it. But certainly with a smile."

"From LivingLab EVERGREEN I made a test set-up for the Clusius Lab, the practical teaching facility at the Clusius College in Hoorn. It allows students to do tests on the request of entrepreneurs. I myself facilitate the hydroponics system that students can use to find answers to different research questions. Look, the system of Botman Hydroponics bears my name, but of course I cannot do it all alone. I also work gratefully with several companies and people. Students can make valuable contributions by conducting smaller, very concrete studies, for example the calculation of working with heat pumps or by examining an idea for supporting the stalks of chrysanthemums. Because they naturally grow upwards, crop support is wanted. And even though some studies do not seem that important, often they are really very necessary to move a step forward. I can imagine that it would be nice that as a student you can contribute to that."

"In cooperation with an organization such as Proeftuin Zwaagdijk, as is now the case within the EFRO EVERGREEN project, there is a valuable reciprocity. They do offer the location and a number of facilities, but the input of knowledge for example comes from two sides, just like the sharing and enlarging of the network. On the other hand, I am also a customer of Proeftuin Zwaagdijk: partly we work together, I take care of other things myself. Most important is the link to practice; in that area we have already achieved so many good results. It is not the case, however, that I am the only one who works on cultivation on water. There is no need for that either: other parties are working on nice developments from their perspective. And that we meet each other is, in my opinion, only an advantage."