How to Increase Humidity in Grow Tent

Last Updated on April 19, 2022

Regardless if you’re a highly-skilled cultivator or just a hobbyist, growing crops can be a difficult task to achieve due to weather conditions, pest infestation, and weed growth that competes with your crops’ nutrients. Fortunately, this problem can be solved with the use of a grow tent.

Given that each plant has its specific temperature, you need to be wary of controlling the desired temperature for your crops to grow. One common dilemma most beginners face is how to increase humidity in grow tent for plants that need enough moisture to grow healthily.

What Is a Grow Tent?

In order to understand the use of a grow tent, it’s practically important to know what it is. A grow tent is used as a preferred alternative in cultivating plants that are difficult to grow.

It’s a transportable grow room that’s suitable for plants that are difficult to cultivate. Indoor plants, for instance, are suitable for grow tent since they’re highly sensitive to weather conditions. Moreover, a grow tent has built-in grow lights for your crops’ insulation which is essential for their growth.

How Important Is a Grow Tent?

There are specific crops that are difficult to grow due to their strict weather requirements. Depending on natural weather alone can be a challenging task as it may vary from time to time. Slight changes in the temperature can hinder the growth of some plants or cause them to deteriorate over time.

Due to the instability of the weather outdoor, some growers seek healthy alternatives for their sensitive crops to grow no matter the weather may be outside. Having a grow tent in your household is more than enough to enclose your plants in one space and receive an equal distribution of the needed requirements like humidity.

This item actually gives growers full control of the climate and lighting for the plants to ensure that they can grow healthily. With grow tent making indoor planting possible, more plants have reached their optimum growth – all thanks to the right amount of temperature and lighting set for indoor plants. 

The Importance of Humidity in Plants

Humidity greatly affects your plant’s growth in such a way that it prevents plants from experiencing water evaporation. Keeping the humidity in the environment high allows the stomata (the pores in a plant that absorb water vapor in the air and enable gas exchange) to be open, hence keeping the photosynthesis working by absorbing CO2.

How to Increase Humidity in Grow Tent

A low amount of water in plants will result in the closure of the stomata which stops the photosynthesis since CO2 is a requirement to keep the said process going. If photosynthesis stops, plants won’t be able to generate food.

Keeping the stomata open is much significant than providing light for your plants.  Even under low light, photosynthesis will continue to occur as long as the stomata are open. However, enough source of light and open stomata can provide optimal photosynthesis.

How to Increase Humidity in Grow Tents

Learning the significance of humidity in plants, you should set an effective way for your plants to experience high humidity levels for optimal growth. Without enough humidity in the environment, this will negatively affect its growth as well as its development.

You can increase the total humidity in grow tents through the following:

Lowering the Extraction Fan Level

Making use of a fan is important to allow proper circulation and distribution of air to the plants. There has to be an exchange between the air produced inside the grow tent and outside source to prevent microorganisms from lurking the place.

Setting the fan level lower minimizes the air to dry quicker in contrast to a high setting. If ever you set the fan level higher, the plants nearby will absorb the vapor. Installing a humidifier can be a good option as well.

Lowering the Temperature Inside the Grow Tent

Decreasing the temperature inside the grow tent makes the air moist, hence providing a higher rate of water vapor for your plants to absorb. As a result, your plants won’t get dried up at all and will instead keep on producing energy through photosynthesis since the stomata are open.

To achieve a low-temperature level inside the grow tent, set your heater lower or airconditioner higher. Another way to drop the temperature is lowering the power of the UV light used for your plants as the heat emitted from the light hastens water evaporation.

As mentioned above, moisture is more significant than light for your plant, as the former will continuously open the stomata in your plant and absorb an adequate amount of CO2 for energy production.

Provide Water Sources in the Area

Placing water sources within the vicinity will increase water vapor levels aside from the moist air. There are several ways in providing water sources for your plants, hence making this process less concerning.

The heat generated from the light will gradually evaporate the water which, in return, increases the humidity in the area.

Add Large Plants Inside the Grow Tent

Instead of seeing larger plants competing against the small ones in absorbing nutrients from the environment, they can instead help in the growth and development of younger plants in their own ways by emitting water vapor from their system.

In addition, larger plants have larger stomata which means that more water vapor will be evaporated to the environment for smaller plants to absorb as well.


Cultivating plants can be a difficult and challenging task since you need to be wary of the weather condition, temperature levels, and even possible pest infestation that might eat your plants. Due to these types of problems, growers start considering grow tent as a better alternative to growing highly maintained plants.

A grow tent allows you to take control over the temperature and overall condition of its environment which is an advantage when handling sensitive plants. To fully maximize your plant’s growth, it’s always best to increase the grow tent’s humidity. To achieve this, you need to lower the extraction fan, maintain proper temperature inside the tent, provide water sources, and place large plants inside. 


Why is the humidity so low in my Grow Tent?

A Grow Tent is basically a portable greenhouse and it comes with built-in lighting and heating facilities. You have a low relative humidity which means that there is not enough water vapor to be held within your air space. Humidity is the amount of water vapor in the air. Relative humidity is the ratio of the amount of water vapor in the air compared to the total amount of water vapor present. You can find the relative humidity using the hygrometer in your grow tent. A relative humidity of 50% or more is usually ideal for plant growth. Raising the humidity level in your Grow Tent is something that you should do at least once a week, as too low humidity levels can cause some plants to wilt.

How can I raise the humidity in my plants using a humidifier?

You can add a humidifier to your plant room to help raise the humidity level. The Grow Tent is designed to be used with a humidifier.

The higher the humidity, the more water your plants will need. You can use a manual humidifier or automatic humidifier to raise the humidity. If you don’t have any extra space for a humidifier, you can also purchase a small, portable humidifier that you can take with you when you go outside.

Humidifiers are good for raising the humidity, but they are not necessary. Some people say that using a humidifier doesn't seem to make much difference. You can use a simple, inexpensive dehumidifier and place it on top of a radiator or underneath a fan to increase the air flow. Make sure that the radiator is not too close to your plants. You don’t want to heat up the air above your plants.

It's important to understand that your Grow Tent will not be able to get humid enough to prevent mold, mildew, or any of the other fungi and bacteria that thrive in a dry environment. This means you will need to increase the humidity in your tent when you are growing indoors.

Use a humidifier with a water reservoir attached to it, as this will ensure that you never run out of water. You can use a ‘sponge’ humidifier to raise the humidity level in your Grow Tent. 

If you use a sponge humidifier, then you must make sure that you add water regularly.

You must also make sure that the water reservoir is clean and that the sponge is not blocked with dirt or mold. You must also remove any dead or dried up leaves from the sponge before adding more water to it.

If you use a sponge humidifier, then you must replace it with a new one every two months.

How can I raise the humidity in my plants without using a humidifier?

You can try putting a towel in the Grow tent. This works, but it's hard to keep track of it. I also tried spraying my plants with water from a spray bottle. This seems to work okay, but there is no way to control the amount that goes on the plants.

Alternatively, you can spray water on the surface of the soil in your Grow Tent.

Do not allow the Grow Tent to get too hot, and ensure that the temperature of the air inside your Grow Tent is set at 75°F.