Humidity levels in different phases of a cannabis plant

Humidity levels are very important when it comes to growing cannabis. Not only for it’s environment and growth, but also for it’s water consumption. A plant is able to consume it’s water through the ground/roots, it’s also possible that it retrieves it’s H2o through it’s leaves (out of the air). This mostly depends on…. Yes! humidity levels:

High humidity: The plant while take it’s water out of the air and through it’s leaves.

Low humidity: The plant won’t be able to get anything out of the air so starts searching water with it’s roots.  

However: Every phase in the life of a cannabis plant requires a different humidity level and way of water consumption. In this article we will dig deeper in humidity levels and different phases of the plant!

First of all:

Humidity simply means: The amount of water that is in the air in that particulair area. One thing to keep in mind is that the humidity often coherents with a certain temperature. Thats why we often speak of “relative humidity” Which means: The current amount of moist in the air, compared to the maximum amount of water that could be contained at a certain temperature.


Humidity in different phases:


Clones do like to have a very high humidity. Thats why you always see them in those very moist, transparent seedling boxes or covered in transparant cups. Especially younger clones are struggling to consume water through it’s roots simply because they don’t have any! This means that they are (almost) fully depending on the water they consume through their leaves. So turning up the humidity levels in their room/box will massively increase the chance of succes.

Seedlings and the vegetative phase

Younger plants that are in their vegetative phase will feel at their best in a humidity of 40-70%. Keeping the percentage at this range will increase the growth of your plant massively. In this period the plant is able to grow lot’s of new leaves and branches because there is still enough moist in the air for them to consume. This eventually leads to a faster and more extensive growing plant.

Once you see wet spots arise on the leaves of your plant, your humidity is a bit too high and you should adjust it a bit lower in the 40-70% range. However, don’t take it too low! If the humidity is under 25% it will be too dry and growth will decrease.

Flowering phase 

This is the most volnerable phase of the plant when it comes to humidity. Flowering cannabis plants really don’t like a moist climate. The main reason is that fungus and bud rot loves to grow and take over a plant if the humidity is too high. Next to that they consume almost all of their water through their roots now.

In the start of your flowering phase (transition from vegetative to flowering), you should aim at at a humidity of not higher then 40%. Once the weeks pass and you are getting closer to the yield, you should lower it even more to around 30%. Because of these dry conditions, the plant will protect itself by producing more resin (which off course is positive!).

Humidity when drying cannabis

Drying your weed is an art and if done wrong, it could ruin very good cannabis! The trick is to dry your weed as slow as possible. The longer it dries, the better the taste and smell will be. So a very dry room is not really perfect as it takes the moist out of your buds pretty quickly. However it should not be too moist as well, this will increase the chance of fungus which your should really avoid!

We recommend to choose for a balanced humidity around 50%. This will give your buds enough time to slowly dry out and getting a nice smell while you avoid the chances of fungus growing in you cannabis. It’s very important te keep track of the temperature in your drying room so we recommend to place a hygrometer around your drying buds.

More about drying cannabis!

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