A plant with healthy growth produces moisture due to plant evaporation. At night without lighting, it is only a small amount; a maximum of some 25 grams/m2/h, depending on the type of plant and its size. However, if not enough moisture is expelled, this can accumulate and cause great problems.
As long as the outside is cold, moisture will be expelled via condensation on the greenhouse ceiling. To the extent that the outside temperature increases, this degree of condensation will decrease, and moisture will have to be expelled using ventilation.
A good and stable climate control is obtained by using the minimum vent position humidity based on the deviation between the inside and outside temperature. If the deviation between the inside and outside is higher than 8 to 10 degrees, vents can practically remain closed. If the deviation keeps decreasing, a proportionate vent position of some 10% maximum can be used.
If you are working with the next generation cultivation with a completely closed energy screen, a larger vent position can be used with accumulating humidity content, for instance 20%. At higher wind speeds, this vent position can automatically be decreased once again via the “leeside vent position humidity wind influence ViP” setting. As this control works in accordance with basic physical principles, this will result in a good and stable control with few readjustments of the vent position.
For more information
Hoogendoorn Growth Management
Westlandseweg 190
NL 3131 HX Vlaardingen
Postbus 108
NL 3130 AC Vlaardingen
T +31 (0)10 460 80 80
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