Humidity

Humidity is another important consideration in grow room management. If it is allowed to get too high for prolonged periods, it will cause problems both in your room and amongst your plants. The main danger is the development of Botrytis or grey mould amongst the flowers or fruit. This organism thrives in conditions of high humidity and will quickly spread and ruin a crop. Plants of the melon family and strawberries are particularly susceptible to fungal diseases and should be provided with a dry environment. The cautious grower will always monitor the humidity in his grow room which is measured by another simple device called a hygrometer. This is a dial type instrument that can be mounted on the wall next to the Max-Min thermometer and give a constant and accurate reading of humidity. The ideal humidity for normal plant rising would not be much above 50%. If it rises above this, the grower will normally operate his extractor fan until it has been reduced. To keep this potential problem under check, it is advisable to avoid leaving water on the floor which can then evaporate and raise humidity. Any water or nutrient solution that spills or overflows should be wiped up promptly and nutrient tanks should be covered at all times. Any water that is left exposed to the heat from your grow lights will rapidly evaporate and add to the humidity levels. Keep your greenhouse or grow room dry.