At WaLeRo, a grower of sweet peppers in Bleiswijk in the Netherlands, Transpar is applied to the greenhouse around mid-May. This Sudlac coating helps create a more comfortable greenhouse climate that enhances the plants’ performance. "Transpar is user-friendly and affordable," says Luc van den Bosch.
"Some coatings require complicated instructions about their application and workings. That is not the case for Transpar," says Luc van den Bosch, crop expert at WaLeRo. "This is the fourth year we are applying this coating and we know what it can do for us."
WaLeRo, a combination of the first names of the brothers Walter, Leon and Ronald van den Bosch, grows yellow peppers of the Gialte (7.7 ha), WLS 1225 (5.7 ha) and Florate (1 ha) varieties at two locations in Bleiswijk. Each year around the middle of May the roofs of the two greenhouses are sprayed with Transpar. The two greenhouses are similar in type but differ in terms of the glass’s dimensions and are positioned differently in relation to the sun. One location has a single-pane venting system, while the other has a double-pane venting system. Both locations are equipped with a double movable screen. "As long as the greenhouse roof is not coated, we use the screens to save energy and to block some of the radiation. After the coating has been applied, we only use the screens to block the sunlight that enters through the open vent windows," Van den Bosch explains.
Done in a few hours
WaLeRo contracts out the application of Transpar on the greenhouse roof to HPW Spuittechnieken in Rotterdam. The sweet pepper grower has had a positive experience with this company. "We like to see the coating applied in short order during an already busy time for the contractor but we are always able to make the necessary arrangements in consultation with the company’s owner Gert-Jan van Hattem. HPW looks after the machine and the coating and in a few hours, they are done." To ensure proper adhesion of the Transpar product, Van den Bosch removes any dust and dirt from the greenhouse roof itself. "We have our own greenhouse roof- washer and use it make sure the greenhouse roof is washed shortly before applying the coating."
Van den Bosch considers Transpar user-friendly and affordable. "You apply it and it does what you expect it to do." In his experience, Transpar provides for a more moderate climate that improves the sweet pepper’s performance. "By the middle of May, you will already see some wear in our main variety Gialte: the leaves are not as bright green and you can see that the plant has to work hard to produce. Transpar blocks heat and moderates the radiation. The coating keeps the plant’s temperature lower and enables the variety to continue to produce better. In addition, it reduces the chance of burning or blossom-end rot. Furthermore, the coating creates a more pleasant temperature for our staff to work in. That is also important."
As it has been on the greenhouse longer it wears off somewhat. "And that’s perfectly acceptable," says Van den Bosch. "There is less need for the coating at the end of the season. When the plants start producing the last fruit setting, we often pass the greenhouse cover washer with only water just once. This slightly thins the Transpar layer, allowing some more light and heat to enter the greenhouse."
During the crop change, the roofwasher makes a last pass over the greenhouse roof. To completely remove the coating, Van den Bosch fills the connected dosing pump with the Topclear cleaning agent. "A clean greenhouse roof is a good start for a new growing cycle."