In 1992 the first wind machine was installed at Vogelaar in Krabbendijke by the Belgian “Frost Protection”. There are now around 1,800 such wind machines in Europe and around 40,000 Orchard-Rite wind machines worldwide. "Night frost, partly due to climate change, is an increasing challenge for the grower," says Jan Bosmans of Frost Protection. "Over 20 years ago, our wind machines were used once every 3 to 4 years. In the meantime, we have customers in France who use the wind machines annually to protect their crops, because the frost nights have become worse. Our wind machines have successfully protected at temperatures of -6 ° C in the cultivation of cherries in Hungary this year. "
The wind machines that Frost Protection (parent company Ghent Supply) offers are from the world market leader Orchard-Rite and are powered by a motor of 150 kW or roughly 200 hp. The machine mixes warm (inversion air) with cold air on the ground. Due to the optimised shape of the blade, this mixing takes place up to more than 150 m from the machine. Because the machine rotates on its own axis, it protects a circular area of about 7 hectares at a temperature of -3 ° C.
“Our wind machines are currently being used to protect potatoes, olives, avocados, stone fruit, kiwis, berries and top fruit, among other things. And this over the three seasons (autumn winter, spring). In fact, wherever it is economically feasible and where night frosts cause problems, installing a wind machine is profitable,” says Jan. “North America is the country where most machines are located. There are many wind machines in the states of Washington, Florida and California, which have prevented a lot of damage over the years. "
"One of the cheapest anti-frost solutions"
Wind machines can easily be combined with hail nets. “Although hail nets are used in an increasing number of crops, this does not affect the operation of the wind machines. Wind machines and hail nets go together with ease. In France, this combination is widely used to minimise risks,” continues Jan.
“The wind machine is one of the cheapest anti-frost solutions per hectare. Especially since the life of the machine is more than 30 years and the annual maintenance / operation only amounts to one man-hour per year. The main disadvantage of the machine is that it makes a lot of noise. That is why a quieter Orchard-Rite machine has recently become available. This machine protects slightly less area, but should only be about 300 metres more away from inhabited buildings. "
Early rather than late
For the machine to work optimally, it is important that it runs parallel to the slope of the terrain. “That is not a problem in Zeeland, but in Limburg and other European countries they often have to be placed at a slight angle," says Jan. "Something that is only possible with Orchard-Rite machines (if we don't consider the mobile toys from New Zealand)." For proper operation, Jan advises all his customers not to follow the consignments as described in the literature (start at + 0.5 ° C), but to start much earlier. Better to start too early and use a little more LPG than too late and lose part of the harvest. Starting and stopping happens completely automatically.
A German study by the Bundeswetterdienst has shown that if global warming continues and will continue, the risk of night frosts will increase significantly over the next 20 years. That is why it is important for the grower to be prepared, so that he or she can guarantee his yield. “In the future we want to continue to focus on improving the current machines, but also on developing frost protection for the smaller plots. That is why we will be introducing a scoop on the market in August, so we have to wait a little longer for that," Jan concludes.