As indoor growers, they are maintaining the relative humidity at an ideal level can at times be dangerous and cause issues.
Experienced indoor growers know that the ideal humidity level in your grow tent is basic to effectively growing indoor plants.
In the event that the humidity is too high in your grow tent, how to bring down the humidity in the grow tent can be a bit of a task.
High humidity levels can prompt stunted growth, bud decay, contagious growth, buildup, and moulds.
Such factors undermine the existence of your plants, including your odds of high yields.
Your grow tent should not have a humidity level higher than 70 per cent.
Thus, in case you are going beyond that level, you need to figure out where the moisture or humidity is coming from and how it can be dealt with, preventing it from damaging your plants.
Do not worry! Maintaining a low level of humidity in your grow tent could be settled by the very things found in your grow tent.
We hope you are not one of them who would lament the whole money, time, and effort since you couldn’t manage a situation like this.
Nonetheless, this article is the outcome of our extensive research on every possible method to keep the humidity of your grow room at bay. We have given both quick and long-term solutions, with a list of reasons that may instigate humid air.
Understanding Relative Humidity

Let us start off with a basic concept: humidity is simply the water present in the air.
In the interim, relative humidity is the ratio of the current outright humidity to the highest possible absolute humidity.
In simpler terms, relative humidity is the air totally immersed with water vapor, and so, all in all, it cannot hold it anymore.
Always remember that water vapor will be present in the air at all times. The air will hold more water vapor when the temperature in your grow tent is higher.
Heat in a grow tent makes the water move quicker through the air, bringing about higher humidity.
Why High Humidity Is Bad And Causes Problems
Till now, you have been told that high humidity is essential to make sure your plants grow in a healthy manner.
Plants love high humidity.
While this is true, an exorbitantly high humidity level in your grow tent can prompt more damage than anything else.
On the off chance that you do not want your grow tent to:
- Become the breeding ground for microbes and molds.
- Make your blooming plants experience the ill effects of bud decay or botrytis.
- Amplify danger from bugs and viruses.
- Forestall transpiration or exchange of air for your plants.
- Support undesirable microbiological growth.
- Obstruct the stomata and decrease carbon dioxide consumption, which is fundamental for effective photosynthesis.
- Make the roots torpid by reducing their innate capacity to take up water.
- Dial back your plants’ supplement intake.
- Limit your plant yield.
Then, at that point, it is an ideal opportunity to see how you can keep up with low degrees of humidity in a grow tent.
How is High ‘Excessively High’ for Grow Room Humidity?
As we probably are aware, the humidity level shifts from stage to stage. In this way, it is impossible to determine a fixed relative humidity percentage as an indicator among ideal and too high humidity levels.
In any case, the rule is, the general range of humidity in a grow room lies beneath 60 percent. A rise in humidity level above 60 per cent can bring in a few risks to the harvest, which we have already discussed in the earlier segment.
Nonetheless, to have an unmistakable idea of what is the relative humidity cutoff of each growth stage, we have got you a stage-wise guide.
The Correct Humidity Levels for Different Grow Stages
Germination/Cloning: Rh 75-85%
At this stage, the underlying growth of the plant’s roots takes place. So a high humidity level is a must. Humidity vaults are used to increase the relative humidity of the air over the seedlings.
Vegetation: Rh 40-60%

Humidity must be somewhat high on the grounds that grow plant leaves would require an ample amount of water present all around. A fractional part of the water consumption is done through roots also. However, as they are not completely developed at this point, leaves need to keep taking water.
Flowering: Rh 35-50%

This is the stage where high relative humidity begins to show its harmful indications. So it is exceptionally important to guarantee no rise in humidity. Moreover, molds, bad buds, and so forth will begin to happen.
Toward the start of the blooming stage, the relative humidity ought to be kept under 40 to 50 per cent. Yet, as the buds begin to deliver a yield, growers lower it down to 35 to 40 per cent. Also, remember to do this gradually instead of dropping down the relative humidity all of a sudden.
Harvesting/Drying: 30-40%

At this stage, the plants begin to dry and bring about the yield. Yet, we need to keep a 30 to 40 per cent humidity level not to let the buds dry very quickly. A few growers love to adhere to somewhat higher humidity (around 50 per cent) to allow the buds dry more slowly. This is in any case, works on the nature of the cured buds.
How to Decrease Humidity in Grow Tent/Room?

Active Ways
At the point when you are looking for ways to bring the humidity down in grow room or room, things are simply difficult to manage. Any step will set aside sufficient effort to bring the relative humidity down. So you need to adhere to the quickest ones.
The several ways that we are going to discuss here, especially for such circumstances. Here you go-
Use An Air Conditioner
We know that the temperature and the humidity of a grow room go hand in hand. On the off chance that the temperature rises, the capacity to hold water vapor in it rises as well, and you see an immediate increase in the relative humidity in your room.
Then again, on the off chance that you figure out how to cut the temperature down, it will eliminate humidity from grow tent/room to a reasonable degree.
Having said that, using the right size of Air Conditioner units is very significant. Else, it will either wind up in buildup or will, in any case, not be able to control the temperature and humidity.
Use A Dehumidifier:
Clearly, to turn humidity down, you must call our companion in need – the grow room dehumidifier.
In any case, before buying a dehumidifier, take a moment to think about the right size for your grow room setup.
Anyway, what characterizes a decent dehumidifier that can take the specific humidity out that you need to? Here are a few things you can take into consideration:
- It needs to be of the specific dehumidifying limit that your grow system calls for. Basically, it should remove the same amount of vapor that your plants transpire through their leaves. This limit is measured in pints.
- In case you are living in a humid region, make sure that your dehumidifier can be connected to the drainage system.
- It needs to have a huge enough water tank.
- It should have an automatic timer or a programmed shut-off feature (when the tank is full).
- It needs to be gentle to the power bills.
Whenever you have the right size of a dehumidifier, you must put it in the perfect spot. Likewise, try not to plug these dehumidifiers into the electrical extension leads.
Passive Ways
For smaller grow systems like 4×4, 5×5, 8×8 grow tents, using a dehumidifier or Air Conditioner is anything but a good solution for bringing humidity down. There are a few passive ways that are perfect for managing this issue in such indoor grow systems.
We have a list of some effective passive ways to do that. Let’s get into it!
Use The Right Size of AC Units:
Both big and small Air Conditioner units may give a spike to the temperature and humidity level.
For larger Air Conditioner units, the dead band ends up being really short, which gives the nearby air an ascent in humidity.
Furthermore, the small Air Conditioner units incite shrinking as an issue for indoor plants. It may establish a hazardous environment for the plants, and high humidity is one of them.
The conclusion? Always use the right size of Air Conditioner units that can run predictable cycles for an extended period of time.
Protect Your Grow Space from Outdoor Humidity:
Some of the times, you see the humidity level go higher and higher regardless of how much effort you put in the wake of putting it down.
That is because, possibly, your indoor nursery is in direct touch with a humid external climate. The region where you live might have higher humidity than expected.
To fix it, commercial growers often use barriers like foam encasings and so forth to prevent the present situation. However, at the point when it is a grow tent rather than grow room, protecting the growing area turns out to be way simpler.
Use Soil That Absorbs Vapor
To dispose of humidity in grow tent, a viable step can be using soil that can ingest water and keep the relative humidity under control. A great example of such soil is sandy soil.
Be that as it may, ensure your plants do not have any issues in growing in such mediums.
Find Exposed Water Surfaces
It is a very basic and cheap hack to do yet ends up being really powerful to bring down the grow room humidity. Furthermore, that is to derive bare water surfaces in the grow room.
So from where do, these exposed water surfaces come from?
– Stale water that does not pool on the ground.
– Water reservoirs.
To deal with the first, you need to make sure that you have a sound drainage system all through the whole grow system. Furthermore, to end the subsequent one, simply put covers on every single water repository you have in the room.
Try not to Depend on One-dimensional Ventilation
Proper humidity is, if appropriate ventilation goes on across the whole grow room, the air won’t ever be soaked with water vapor. To ensure it occurs, you can’t rely upon the oscillating fans, as it were because they can just lessen the temperature of the plant.
All in all, how would you initiate a multi-dimensional ventilation system? All things considered, here are a few ideas.
Make sure that there are multiple inlet holes in case you are growing in a tent.
And if it is a grow room, make sure that you have more than one source of intake fan.
Also, ensure a proper airflow all through the bottom (floor fans) and top part (wall-mount oscillating fans) of the plant overhang. Try not to let the carbon dioxide-rich, heavy air develop on the floor.
Watch Out for Your Humidity Level
This is not a ‘prevention’ to decrease humidity in grow tent. However, using a hygrometer can keep your eyes on the specific humidity level your tent/room is going through.
There are a lot of different thermometer-hygrometer combos available on the internet. With one of those hung up on your grow tent wall, you can kill two birds with the same stone.
That being said, we hope that these ways work well for you with respect to reducing the humidity level in your grow tent.