Removing coatings: how to get your greenhouse spotlessly clean

This summer, some rose and vegetable growers started removing the coatings from their greenhouse roofs as much as ten days earlier than last year. “The season doesn’t usually start until mid-August, but we’re already working on it now,” reveals Dennis van Veldhoven, just back from his summer holiday. This summer looks set to be a repeat of last year’s, although it could still turn warm and dry in September. But that would present him with a new challenge, because a heavy rain shower is needed to rinse off the coatings. And if the rain stays away, he will have no choice but to spray the roof again. “So we’re constantly checking the weather on five or six different weather apps. Although they aren’t always accurate anyway. A thunderstorm can be very localized, which can make things quite difficult. Sometimes I feel like one of those TV weathermen. So it’s a constant stop or go situation for us.”

Weather forecast

Removing coatings therefore starts off with the right weather forecast. “You need dry weather to apply ReduClean, ideally for a couple of hours.” Those couple of hours are needed to allow the remover to react properly with the coating. After that, you need a good downpour within the next two or three days, because if the rain stays away for much longer the glass may not come completely clean.

ReduClean is the perfect product for coatings like ReduSol, ReduHeat and ReduFlex Blue. For a special coating like ReduFuse (IR), you’ll need a stronger product: ReduClean for ReduFuse. Dennis: “White chalk products can wear off, particularly with the heavy downpours we have been getting lately. But diffuse coatings are extremely rain-resistant, so you need a stronger product to remove them. ReduClean for ReduFuse (IR) works really well. It leaves your greenhouse spotlessly clean after a good downpour. But you do have to make sure you cover all the coating when you spray it on.”

CONDITIONS

To ensure even distribution, the greenhouse roof must be dry, the machine must be properly adjusted and the product should be diluted in a ratio of between 1:5 and 1:7, Dennis says. “We always ride along with the sprayer on the roof so that we can intervene straight away if a nozzle gets blocked. It all has to happen very quickly because the vents have to be closed, of course. And you can’t leave them closed for too long, otherwise you risk damaging the crop. With an ideal gutter length, we can do 1.5 hectares in an hour. Most growers therefore prefer to outsource the work, although a few still do it themselves.”