The latest LED and plant growth information from our specialists


Humidity and Growing Indoor Plants

VPD or vapor pressure deficit is important when it comes to maintaining plant health.

As the ambient temperature changes, it affects the rate of transpiration. For optimal plant growth a balance has to be maintained.

High VPD can cause plants start to take in too much water from the roots.  This can result in a burn pattern or curled leaves.

If you’re feeding your plant nutrients then the plant can uptake the nutrients too fast resulting in leaf tip burn.

Low VPD can cause slow water uptake resulting in nutrient deficiency, weak growth and inviting the plant to insects and a number of diseases (wilting, curl or crisp leaves).

Here are some guidelines around how you can maintain the perfect VPD in your grow area.

Grow Room Environment

One of the most important aspects of indoor growing is keeping your grow room environment right on the sweet spot. That means keeping the air fresh, keeping a set temperature range, and keeping a set humidity range.

Air Changes

Your Grow area needs to be set up to have at least 3 complete air changes per hour.


Minimum 18 Degrees/Maximum 31 Degrees for most plants


The Level of humidity that plants need in an indoor environment depends on the temperature of the environment. For instance, at 26 Degrees Centigrade Humidity must be at least 70% to prevent the plant from excessive transpiration (When the plant sweats too much).

VPD – Vapor Pressure Deficit

It is important to monitor temperature and humidity levels and keep your grow area within the required zone of the chart below.

The best temperature and humidity for indoor gardening
vpdchart 1 scaled 1 1536x1086 1

Get a downloadable and printable PDF by clicking here

It can be tedious trying to monitor and maintain the humidity in your grow tent at all times.

To remotely monitor your tent’s humidity and temperature, check out our Monitoring combo, to remotely monitor and control the temperature of your tent, check out the Wifi Temperature Controller and probe.