Safer® Hydro FAQ: What Is The Right Humidity For Growing Plants Indoors?
The answer depends on where the plants are in their growing cycle. When germinating and growing their first roots, plants need consistent moisture. But a soggy climate can lead to fungal diseases, such as damping off, that can kill seedlings before they become established.
The ideal humidity for them is around 50 to 60 percent.
During the vegetative stage, when your plants are growing lots of thirsty leaves, the need for moisture spikes and they thrive in humidity levels up to 70 percent. As plants begin to bloom, they require less water and a less humid environment will prevent the fungi that cause bud rot from moving in.
As the flowers open and mature, the humidity should be reduced to below 50 percent to further ward off destructive fungi.
During the last stages of flowering, 40 percent humidity is ideal. A fan blowing gently but steadily around plants helps to keep the humid air from settling on leaves and other surfaces in your indoor garden.