“Clear relationship seen in ProJoules between excessive leaves and loss of production”

A grower in Spain, for whom Willem van Dijk is a cultivation advisor, starts with ProJoules. The Spanish grower will soon be the fifth grower ‘from Willem’ to use the crop planning platform. Willem and the international growers started working with the ProJoules platform in earnest this year for the first time. The cultivation advisor shares his experiences.

Willem got to know the platform when it was still in the Excel phase. Data were originally collected in Excel. The Joule was and is a leader. “It came about by chance that I started working with it. Growers asked for it. I know the creators of the platform and can explain to the growers how it works.”

Much has changed since the initial phase of ProJoules. “You can no longer compare the platform today to how it once started.” It is obvious that the platform is now available online, but it is not the only one. “Users now have a much better overview of the dashboard in ProJoules. You can also make graphs in Excel, but that’s better.”

Insight into cultivation strategy
The growers that Willem works with are located in Germany, the Czech Republic, Austria and soon also in Spain. “In addition, I also guide growers in England, Japan, Vietnam and Mexico, primarily from a distance.” Of these growers, mainly active in tomatoes and also some with cucumbers, growers in Austria, Germany, Mexico and soon Spain are using ProJoules. “In the latter case, I advised the growers myself with ProJoules. It is a brand new company in Spain. Growers cannot yet rely on the experience of a long gardening career. With the platform, I can give growers better insight into why they have to make certain decisions. The lines in the graphs in ProJoules quickly provide insight into why a certain cultivation strategy works or not.”

It’s not like growers with a lot of experience can’t also use the platform. In fact, Willem also has a lot of experience himself, but he still gains new insights thanks to the platform. “What I have seen from my growers this year is that they can push the boundaries even more. For example, growers began pruning timbers earlier in the summer and continued cultivation longer. It gave better production. You can also see on the basis of the data in the platform whether it pays to keep an extra fruit at the start of the year.”

Cultivation data remains with the growers
In 2021, Willem ran a test with growers. This year, the online platform started in earnest. “It is fantastic that the platform continues to develop. This morning I saw an update with CO2 figures and temperature integration in ProJoules,” says Willem at the end of November. “Looks very smooth I must say.” The ProJoules platform regularly publishes new updates, with the aim of gaining even better insight into the crops. More and more data is becoming available in the greenhouse that ProJoules can also use. “The growers can make it as extensive as they want. This also applies to ProJoules. Growers do not need to use all available data.”

According to Willem, what appeals to growers when using the Dutch-made crop planning platform is that the cultivation data stays with the grower. “I have heard that several times from growers. They decide who can access the data. Data is not simply shared. The grower must also give me real access as an advisor to be able to watch.”

View data from ProJoules. Click here for enlargement

More leaf picking etc
At one of the growers that Willem oversees, Drechsler, a record production* was achieved this year, thanks in part to insight from ProJoules. “However, we still see room for further improvement,” says the consultant. “At a certain point there was too much leaf mass on the plant, and production suffered a blow. Next year, we will pay even more attention to the employment history and remove leaves on time.” This year, the German growers already decided to pick extra leaves because of the insight provided by ProJoules. “It pays off until the beginning of September. It is certainly not the case that as soon as it is summer, the grower can retire and rest on their laurels. There is still a lot to do in the fall in terms of crop maintenance.”

Lighting is not an option for many growers this winter. Adviser Willem is not quiet anymore, also because he also has growers in other regions. In Mexico, growers are busy in December. “Data in ProJoules shows that growers have been keeping too many units in October to December for years. As a result, production was often lower at the beginning of the new year. The load on the plant was too high. The advice I give now is more pruning back. Sometimes the growers didn’t prune at all.”

Light measurement in foil greenhouse Mexico

Light measurement
Another great insight from the platform is that the growers see how important it is to know the amount of light in the greenhouse. “The light transmission of a good foil greenhouse today sometimes comes very close to a glass greenhouse with all the available techniques.” Willem also carried out light measurements in Mexico. “We were surprised by how much light came into the greenhouse from outside. Even a little more than with glass, but the difference was minimal. Growers also benefit from such insights. They are very open and eager to learn. It is nice to work with them.”

There is also plenty of activity in Europe. An Austrian grower Willem works with lights up, at least until Christmas. “Power is uncertain after Christmas. If less power is available, the grower will light less. With ProJoules, an additional plan has already been created with insight into which plant load the grower must comply with. Based on the available joules, a grower must adjust the plant density or the pruning policy, also in a general sense.”

See more at joule
In Willem’s opinion, growers still pay too little attention to the plants’ energy balance. “Growers are still very dependent on feeling and experience. Like: ‘Then the light rises outside, then this or that must be done.’ These kinds of choices are now more substantiated.” For the consultant, it is easy that it is better to give external advice. “You are now discussing the same numbers, it is easier to talk about. Otherwise, you have to go and explain to someone why you want something in cultivation, without being able to point out it. Now you point to a line and a week, and ProJoules shows why a particular course change is necessary.”

Willem concludes that the use of ProJoules further helps growers and advisors. “It makes me stronger, but so does the customer.” However, he is not afraid that he will no longer be needed as an adviser. “Completely autonomous cultivation is, in my opinion, a utopia. To feel that the climate is still necessary. A number alone does not say everything. Everything may look good on a computer screen, but when you get inside the greenhouse, it may not be quite right. Just look at Drechsler. We are very satisfied there, but we still see room for profit.” Willem would like to see more figures. “For example, even more numerical insight into the foliage of a crop.” Optimal cultivation can be achieved by combining experiential insight and numerical cultivation.

For more information:

William van Dyke
Green Management van Dijk
+31 612 683 871

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