Multiple thin layers ReduSol
Dutch chrysanthemum grower Hein van Wordragen applies coatings to the greenhouse roof himself instead of using a contractor. This way he can determine precisely the timing and thickness of the layer. He works with several thin layers on top of each other.
There is always one day in spring when the contractor’s phone rings continually. The weather forecast is good: Sunny and dry. It’s ideal weather for applying a coating, which is necessary to protect the crop against sudden bright radiation. The consequence is that the contractor has to juggle his schedule in order to meet all the requirements of his customers. Three years ago Hein van Wordragen decided that he no longer wanted to be dependent on someone else’s schedule. “By using a customised roof washer we apply ReduSol ourselves. This way we can decide the precise moment of application ourselves,” he says. Van Wordragen grows exclusive varieties of chrysanthemums on 4.3 hectares in Bruchem, Bommelerwaard, for markets that value bright colours and heavy quality flowers, such as Russia.
By doing it yourself you can also vary from the normal pattern. The nursery is one of the first to apply several thin layers on top of each other. “We apply the first thin layer at the end of April. After that, as we approach the summer, we check the light development and based on that determine when to apply a second layer to further shade out the light. We can decide this day by day.” And there are more possibilities, he says. Coat a few bays separately or even wash some off if necessary. Building up the coating in thin layers matches the increase in light in the spring. The colourful flowers benefit from a coating, but also receive sufficient light for proper growth and good colouring. “If you apply a thick layer too early there is too little light for growth. But if you only apply a thin layer it doesn’t have the strength to last the whole season. Therefore the answer is to apply several thin layers.” In addition, the natural predators benefit from being protected from the sun. “The biological control functions much better when the sun is not too strong,” he says.
Train an employee
There are two conditions to the approach used by Van Wordragen. You need to have your own roof washer and you have to train one of your employees. Coating remains a specific job that requires care and expertise. ReduSol application and roof washing can be done with one machine. Before applying the coating in the spring the roof has to be washed one more time. After that the dosing pump can be fitted to the washer where it can remain until the autumn and all the Redusol has been applied. Then it’s time to the wash the roof again.