There are days when clouds and sunshine alternate constantly. "Then you are constantly faced with the choice: do I close the screen or not?" With ReduFuse, cultivation is much more relaxed," says pepper grower Wibo Valstar.
Pepper growers regularly disagree about the benefits of a diffuse coating. "In our excursion group, half of them don’t use it, and the other half does. The first group argues that it reduces the light a little bit in April, the second group thinks that the benefits are greater. We do not see any negative effects in April", according to Wibo Valstar.
Together with his brother Ewout he has two companies in De Lier, together 6 ha, both companies cultivate green peppers. By now they have been using ReduFuse for six years. "We started with it to cool the head of the plant and the fruits in the summer to prevent tip rot. Now we've switched over to the Overture variety, a variety that is already less prone to tip rot. So we cannot properly compare with the situation in the past," he says. "But we do know for sure that it saves on the amount of screen hours. Above 650 watts the fixed screen always will close, but what do you do on a day when the sun and clouds alternate? Then you are constantly deliberating. That dilemma you no longer have with ReduFuse. It gives peace of mind and in the greenhouse. Certainly it is a big advantage in the weekend."
Even greenhouse climate
ReduFuse distributes the light in the greenhouse, creating an even climate. Moreover, the light penetrates deeper into the crop. This way the head of the plant receives slightly less radiation, while leaves at the bottom participate more in photosynthesis. Another big advantage is that there are no more sunspots. It is precisely in these sunspots that the stress mounts quickly and the stomata close and thus the CO2 absorption is less, causing a reduction in photosynthesis; the crop thus becomes less active. "We can close the ventilation windows on the windward side a bit more with the diffuse coating. This ensures that the CO2 stays more in the greenhouse and also the air humidity stays higher. The plant feels better", says Valstar.
Minimum pipe temperature
They have the coating applied in early April. "Better two weeks too early than one week late. In the spring you have the transition from dark to bright weather and that still causes stress for the crop. With the coating, the effect is reduced. If you are too late with applying, you get the situation that you always have to close the fixed screen," he says.
He acknowledges that in the beginning the reduced irradiation requires some adjustment. In the morning they have to use heating a bit more. "We raise the minimum pipe temperature by 2-3 °C. You have to put in a bit more energy. But for us that is not a problem. The benefits far outweigh that."
A special point of attention is the direct solar radiation coming through the open ventilation windows. This is barred with the double screen, with one of the two closed by 20% and the other by 10%.
At the end of August, the coating will be removed from the greenhouse roof. The decision is based on the number of small fruits at that moment; they are vulnerable. If there are many, ReduFuse stays on the roof for one more week. Also the weather forecast plays a role. "We are satisfied with this approach. This way we have good control over the greenhouse climate and we can deliver top quality peppers", he concludes.