How To Raise Humidity In Grow Room Without Humidifier

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So, the humidity in your grow room is too low and it’s causing a bunch of problems to occur. Yes, having too little moisture in the air in your grow room can cause some pretty serious issues with your marijuana plants.

Most people would tell you to just use a humidifier for an easy fix, but maybe you don’t have a humidifier, or can’t use one for whatever reason. How to raise humidity in a grow room without a humidifier is therefore a big topic we want to address.

Now, raising the humidity level in a grow room without a humidifier is possible, and quite simple actually. You can slightly decrease the temperature, decrease ventilation, add more sources of moisture into the grow room, and you can use slightly stronger grow lights too. Let’s explain how all of this works right now.


Why Not Use A Humidifier?

Well, there are several reasons why you might not want to use a humidifier, or why you can’t as well. Why aren’t you using a humidifier in your grow room or grow tent?

  • The humidifier might just take up too much space, space you don’t have to spare.
  • Humidifiers can be a couple hundred bucks or more, especially for good ones.
  • Humidifiers are not always accurate and can be hard to control.
  • A large humidifier is going to make a lot of noise.

Raising Humidity In A Grow Room Without Using A Humidifier

There are a few good ways to raise the humidity in your grow room without having to use a humidifier. Of course, none of these methods are nearly as effective as using a humidifier, but they do help a bit.

Moreover, if you use these methods in combination with each other, such as two or three methods at once, you may be able to achieve the same results as with a decent humidifier.

1. Lower The Ambient Temperature

If you did not already know, a simple scientific rule is that the warmer air is, the less moisture it can hold, and cooler air is, the more moisture it can hold. Now, you do of course have to maintain the proper temperature for your weed plants during all growth stages.

However, if the temperature in the grow room is on the high end of the spectrum, you can afford to lower the temperature a little bit.

There are various ways of lowering the temperature in a grow room, including using LED lights or grow lights with integrated cooling, using an AC system, or creating more ventilation. If you lower the temperature in the grow room, the cooler air will be able to hold more moisture.

2. Provide Your Weed Plants With More Water

To raise the humidity in your grow room, another thing you can do is to water your plants a little bit more. Once again, there is a fine balance that you need to strike here, because there are of course many problems that can be caused by overwatering your plants.

However, if your plants, the soil mainly, is usually fairly dry, you can afford to wet it some more. The more water is in the soil and in the weed plants, the more of that moisture will evaporate into the air, thus raising the humidity level.

Just be sure that you don’t end up overwatering your weed plants.

3. Spray Water In The Grow Room Regularly

If the soil in which you are growing the weed plants is already fairly wet, one simple solution to raise the humidity in the grow room could be to spray some water over the plants with a little spray bottle.

Of course, this is a super temporary solution, and to maintain ideal moisture levels, it’s something you would have to do several times per day, but it is a solution that works, if you are vigilant about it.

4. Place Cups Or Buckets Of Water In The Grow Room

A really simple way to help raise the humidity in your grow room is to just place some cups, plates, or bowls of water in the room. Ideally, place 1 bowl of water in each corner of the grow room.

The heat in the room, plus the lights, will cause the water to evaporate, thus raising the humidity. This is actually one of the best, easiest, and most effective solutions.

It won’t cost you anything, and if you end up raising the humidity too much, just remove a couple of the water dishes.

5. Use A Fan BUT Decrease Overall Ventilation

Alright, so using a fan won’t exactly raise the humidity in the grow room, but it will disperse the existing humidity better (we have reviewed our favorite fans here). Moisture will gather in specific areas and cause some areas of the grow tent to have more moisture than others, which can mess with humidity readings.

Good airflow inside of the grow tent will help evenly disperse the moisture content in the air. Now, on the flipside of the coin, if you have a lot of ventilation in the grow room, with lots of new air being cycled in and lots of old air being let out, moisture will also escape with that old air being pushed out.

Therefore, to raise the humidity in your grow room, you want to decrease the amount of air being cycled through the grow room from and to the exterior. This will help more of that moisture stay in the grow room.

6. Use Slightly Stronger Lights

The other thing that you can do to help raise the humidity in the grow room is to use slightly stronger grow lights. The fact of the matter is that the stronger your grow lights are, the more humidity they will suck out of the soil and your plants.

That humidity has nowhere to go once it escapes the plants and soil, and therefore will raise the humidity in the grow room. Just be careful that the lights are not way too strong, or else you will run into problems such as light burn.


Remember folks, you need to keep the humidity at a certain temperature for your grow room and your grow tent. Having the humidity level either too high or too low can have serious consequences for the wellbeing of your weed plants.

Try lowering the temperature, add more sources of water to the grow room, and use slightly stronger lights to cause more water to evaporate. Do all of this, and you should have no problems raising the humidity in your grow room without a humidifier.


My passion for the sticky icky started nearly a decade ago, and it all began when I first laid my eyes on the beauty that is the marijuana plant.

I cover all aspects of growing from equipment recommendations to plant health/care tips to help both new and experienced growers.