What does humidity do?

Plants evaporate water in order to cool themselves and to discharge waste. Humidity impacts the amount of water plants can evaporate through their leaves. If the humidity is too high at a low temperature, plants cannot get rid of their water vapor. This stops the evaporation process. If this is the case, plant roots can no longer take on new nutrients as there is no room for them. Therefore, you should always use a good ventilation system when growing indoors. This helps discharge the warm, humid air and promotes the supply of fresh air.

If the humidity is too low at a high temperature, plants evaporate too much water instead. They will try to make up for this loss by absorbing more water with their roots. This means they also receive more nutrients and may lead to what is called a nutrient burn. A nutrient burn first leads to burned leaf tips and may end with dying flowers and withered leaves.
 

Needs of the plant

The ideal humidity of your plant depends on the phase it is in. Cuttings and young plants require a high humidity. This is because their roots are still developing. This requires a lot of water. We recommend a humidity of 80 to 85 percent. As your plant grows you should lower the humidity. In the last weeks of the grow phase we suggest a maximum humidity of 60 percent. Keep in mind that the perfect weekly humidity depends on the plant species.
 

Increasing or decreasing humidity.

Humidity has a large effect on plants then, but how can you influence it? A humidifier is an inexpensive and easy way to increase humidity. You can also leave a wet towel in your grow room. If you are trying to lower humidity, you should use an ventilation system to exhaust more air. Another option is to use a fan or dehumidifier.