Grow Tent

How to Raise Humidity in Grow Tent [10 Working Ways]

How to Raise Humidity in Grow Tent

The grow tent is a fantastic way to grow your plants, and once you master all the small intricate moving parts such as the growth light spectrum, airflow, grow tent temperature, and humidity, you’ll achieve some amazing results. However, the environment can be difficult to master, for example, as your plants grow, their humidity requirements can change, and being flexible with your humidity settings becomes vital. 

How to raise humidity in grow tent? In the following article, we’ll offer the top 10 ways to effectively increase the humidity in your grow tent with and without a humidifier. Additionally, we’ll go deep into the question and analyze what happens when your humidity levels are too low and what your humidity levels should be. Let’s get it started. 

How to Raise Humidity in Grow Tent with Humidifier

Without doing time-consuming manual work, a humidifier can effectively raise humidity in a grow tent with the accurate humidity level that your plants require. To better achieve the ideal humidity level for optimal plant growth, follow the three steps below to know how to raise humidity in grow tent with humidifier. 

Step 1. Select a humidifier that will work for your plants. 

Determine which humidifier is the best for your plants by doing full research about the tank capacity, run time, and coverage area. Depending on the size of your grow tent and the growing stage of your plants, requirements about the above three factors can vary from case to case. 

Step 2. Place the humidifier in the middle of the grow tent.

You may encounter terrible cannabis crops if you’ve placed the humidifier too close to your plants. When plants are exposed to too much moisture but without the ability to dry out, it’s highly likely the cannabis will get sick and create the conditions for mildew to take over. Therefore, it’s suggested to place the humidifier in the middle of the tent for an even dispersal of the mist. 

Step 3. Monitor and control the humidity level in the tent.

Advanced plant humidifiers such as Spider Farmer Cool Mist Humidifier for Plants are often equipped with a built-in humidity detector that directly displays the current metric. Additionally, you can adjust the expected relative humidity level and once it reaches the limit, the machine will automatically stop humidification. With the help of these designs, you can take full control of the humidity level in the tent. 

Spider Farmer 16L plant humidifier

By making use of a grow tent humidifier, how to raise humidity in grow tent becomes much easier. However, if you prefer handwork that’s more budget-wise, check the following 9 ways to increase humidity in a grow tent instead.

How Do I Increase Humidity in Grow Tent Without Humidifier

Below we will outline various methods to how to increase humidity in grow tent without a humidifier. It is important to control high humidity to avoid issues like bacterial diseases and pest infestations. While not all methods are suitable for all growers or grow tents, we’re sure you’ll find some great tips for increasing humidity in grow tent to the optimal level. Too much humidity can create an ideal environment for disease and pests, leading to fungal diseases and bacterial growth.

Solution 1. Put soaked sponges near air vents to raise humidity in the tent

This method works best if you are using a small and vertically oriented tent with shelves. Since this type of tent doesn't have much space, the sponge will quickly dry out by the effect of the heat and airflow, producing evaporated water over time and therefore, increasing the humidity level in the grow tent.

use soaked sponge to increase humidity in a grow tent

Solution 2. Hang wet towels for a quick fix

Similar to the method above, hanging some wet towels close to your grow tent inline fan is a pretty affordable and easy way to add humidity to your grow tent. Air being pumped into your grow tent will absorb moisture from the towels as it passes around and through the towels.

6-Inch Inline Fan with Speed Controller

Solution 3. Place a bowl of water in the tent

By placing water bowls in the tent, you can add a stable and gradual boost to humidity in grow tent. If you have a rather big grow tent with much floor space and air vents, try scattering water bowls in it to consistently increase the humidity level. 

Solution 4. Employ a water spray bottle

Almost every grower has a spray bottle, so this shouldn't be a problem. You may simply spray water every morning and evening on the walls of your grow tent.

use water spray bottle to raise humidity

Solution 5. Add more plants

Plants breathe using a process known as transpiration, and maintaining the right humidity is crucial for indoor plants. When they absorb water through their roots, they breathe it out through the leaves, helping plants thrive. Additionally, plants absorb carbon dioxide during photosynthesis, which not only helps them grow but also improves air quality. Adding another plant can increase the amount of moisture in the air, raise humidity levels, and enhance the balance of carbon dioxide and oxygen in your indoor environment.

Solution 6. Reduce ventilation

Too much ventilation can suck all the moisture out of the air inside your grow room. To retain moisture, try adjusting your ventilation and see if the humidity inside the grow tent increases.

Solution 7. Reduce the heat

Reducing the heat inside your grow tent can effectively increase the amount of humidity in the air. Warm air can hold more water vapor than cold air, so as the temperature decreases, the relative humidity increases. It’s a simple and effective way to control humidity. For example, one easy practice is to take off certain numbers of fluorescent tubes or adjust the dimming knob if you are using grow tents with LED grow lights in. 

Solution 8. Mix mature and young plants together

As you start adding plants, especially big ones, the relative humidity in a grow tent will rise since they breathe more and produce more relative humidity compared with young plants. These mature plants have larger leaves and more stomata, which allows them to evaporatively release more water vapor. This water vapor can subsequently be utilized by your growing plants.

Solution 9. Control the ventilation system

Your grow tent's ventilation system ensures that air is being exchanged in and out of it. At various phases of plant growth, try to keep your fans running at a moderate speed to maintain moisture. Setting your fans at high speeds will cause the air to dry up more quickly than usual. To add humidity to your grow tent, you may also try turning down the number of fans. 

What Happens If Your Humidity Is Too Low?

Humidity is the level of water present in the air in any environment. There are two main types of humidity to understand: absolute humidity and relative humidity. Absolute humidity is the total amount of water vapor present in the air, regardless of temperature, while relative humidity is the percentage of water vapor present in the air relative to the maximum amount the air can hold at a given temperature. In this context, we are primarily concerned with relative humidity, as it provides a better understanding of how conducive the indoor growing environment is for plant growth.

Low humidity levels will cause your plants to experience stunted growth which will have a negative flow-on effect on plant yield. We all understand that plants need water to grow and survive. However, no water equals no growth. When you have high temperatures and reduced amounts of water, it can create dry air inside your grow tent.

To offset this, the plants inside the grow room attempt to absorb more water through their roots. This causes the plant to focus more on survival and less on growth, placing the plant under increased stress. Remember, your water is usually full of added nutrients which are carefully calculated. If your plant is absorbing excessive water through the root system, it could be getting too many nutrients at the same time.

Another side-effect of low humidity on your plants inside a grow tent could be fungal diseases such as powdery mildew and other infestations, which all growers want to avoid.

What Should Your Humidity Levels Be?

There are several different stages of your plant’s life that you need to consider when you’re talking about humidity levels inside your grow tent. Below is a VPD Chart that you can take for reference.

grow room ideal temp and humidity level

FAQs about How to Raise Humidity in Grow Tent

  • Is it OK to put a humidifier in a grow tent?

Yes. It's absolutely fine to put a humidifier in your grow tents since it enables the ideal humidity level that your plant requires. You can always adjust the humidity levels when necessary. 

  • Do grow lights increase humidity?

If the growing environment is quite humid, the heat you grow lights produce could possibly evaporate water from your plants, resulting in a humidity increase. However, overall, grow lights have much less impact on humidity compared with other equipment such as humidifiers, dehumidifiers, and ventilation systems. 

  • How do I adjust the humidity in my tent?

The most effective way to adjust the humidity in grow tents is to apply a humidifier such as Spider Farmer Cool Mist Humidifier for Plants. Alternatively, you can raise humidity in grow tent by using soaked sponges, wet towels, water spray bottles, and adding more plants, etc. 

Verdict on How To Increase Humidity In A Grow Tent

Now you'll have a much clearer idea about the important role that humidity plays in any plant growth and how to raise humidity inside your grow tents in 10 possible ways, regardless of whether you use a humidifier or not. With the practice of increasing humidity in the grow tent to a proper level, hopefully, you'll experience fruitful yield with satisfying plant qualities. 

Read More: How to Lower Humidity in Grow Tent


About Ciki

Ciki has been navigating the digital world of SEO for over 4 years, applying her expertise originally in the software sector before turning her attention to indoor gardening. Merging her tech-savvy background with a passion for nature, Ciki offers a unique perspective on gardening, blending modern techniques with time-honored traditions.

7 thoughts on “How to Raise Humidity in Grow Tent [10 Working Ways]

  1. Andrew Ram says:

    I never thought I would struggle to gain humidity. I am stuck at 30% at 83 degrees. I put a humidifier in tent and stopped small clip fan. I fear stunting growth with low humidity. Hopefully I find the sweet spot with one of more of your suggestions. Being a beginner at the grow is pretty intense as the plants go through the stages .

  2. john draper says:

    I reduced intake on ventilation system , I’m now at 60% . Perfect …. Thank you

  3. Jose Martinez says:

    The best products to grow plants!

  4. dougbream says:

    These tips are excellent for new growers like myself, thank you for the knowledge!!

  5. Nick says:

    All really good tips, I noticed in my super dry environment that increasing the intake airflow to help reduce the tent’s temperature allowed my humidity to become more stable and find a happy medium.

  6. stang1238 says:

    interesting deal

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