How do you prevent excessive moisture in a greenhouse?

How do you prevent excessive moisture in your greenhouse?A humid climate leads to various cultivation problems, such as inequality and the onset of diseases in you crop. Therefore it’s important to control the moisture by dehumidifying. Dehumidifying the greenhouse can reduce the moisture supply or increase the moisture output. In this article, our specialist explains how to prevent and how to get rid of excessive moisture in the greenhouse.

Determine humidity

To determine what the extent moisture is in the greenhouse, you should first know what the air humidity is in the greenhouse. The best way to measure the humidity in a greenhouse is to look at the absolute humidity. This indicates the amount of moisture the greenhouse air contains, expressed as the number of grams per m³ of air (g / m3), or the number of grams per kilogram of air (g / kg). If you know what the humidity is in the greenhouse, you can determine if this is too much and if so, how to dehumidify.

Reduce moisture consumption

The more a crop evaporates, the higher the moisture supply, the higher the humidity in the greenhouse. Evaporation is of course important for the absorption of minerals, but excessive evaporation causes excessive moisture in the greenhouse. Therefore, to reduce the moisture supply, you can choose to heat less. This reduces the evaporation and the output of moisture. Please note: with this method you need to be aware that the evaporation doesn’t fall below the minimum, too little moisture is just as damaging as too much moisture!

Increase moisture drainage

Another way to remove excessive moisture in the greenhouse is to increase the moisture output. When you have a screen cloth, it will drain the moisture, which will condense against the cold roof. However in many cases this doesn’t provide enough moisture removal. By creating a small gap in the screen the drain can be increased. The disadvantage of this method is that there’ll be a local cold trap.

Some growers choose to use fans, instead of creating screen gaps. However the windows have to be opened more often. This causes heat loss and thus a higher energy consumption.

Another way to dehumify a greenhouse, is to use a dehumifierThis machine pulls moist greenhouse air through the installation, where the air gets heated and dried. The dry, warm air is then reinserted in the greenhouse and the extracted moisture can be reused. The advantage of this is that no energy is wasted: the used electrical energy and the released heat both come back in the greenhouse and the water is suitable as process water. 

Principe Drygair

Eef Zwinkels
Questions about preventing moisture in a greenhouse
If you have any questions regarding preventing moisture in a greenhouse or you would like us to advise you, please contact our Product specialist Eef Zwinkels or use the question form underneath.


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