Top 8 Ways to Increase Humidity in A Grow Tent

What happens if your Grow Tent room is too hot?


Nobody wants to end up with dead plants or a stinky grow tent room! That’s why keeping track of the humidity levels in your grow tent is essential to ensuring the right environment is at it’s best your special indoor plants.

A drop in humidity results in leaves curling upwards and, if not controlled, will ultimately lead to your precious plants dying! (We don’t want that happening do we?)

Essentially, your grow tent should maintain a humidity of between 45% to 75%. When the humidity drops below 40%, you risk losing your plants. Low humidity stunts the growth and development of your plants, eventually causing a dip in production.

If you are worried about low humidity in your grow tent, this article is for you. It highlights ways to increase humidity in grow tents, supporting your plants’ growth and development [1].

Key Takeaways

The best way to increase humidity in grow tents is by controlling temperature.
Some DIY methods include spraying water on plants, setting water trays near air inlets, mixing large and young plants, and using propagators.
More complex but highly effective methods include installing humidifiers and air conditioning systems in the grow tent.

How to Increase Humidity in Grow Tent

1. Mix Mature and Young Plants

Your grow tent is probably filled with young plants, and while there is no problem with that, it can be a little challenging to ensure the proper humidity levels with young plants. Adding mature plants is a great way to bring in more humidity to your grow tent.

How? Larger plants tend to respire more, producing more relative humidity in the tent. During respiration, the plants release carbon dioxide and water vapor which are the key elements of humidity.

The bigger leaves discharge more water vapor after evapotranspiration, which the smaller plants use. The idea is to distribute the larger plants and space them evenly to ensure consistent humidity levels, adequate light, air, and nutrients for all the plants.

2. Install a Humidifier In The Grow Tent

A humidifier can come in handy to increase humidity in your grow tent. Humidifiers work by extracting a cool mist which significantly increases indoor humidity levels. This can help ensure optimal levels for your indoor plants to grow and thrive.

The good thing about using a humidifier is that you can control the moisture levels. Ideal settings should be between 50% to 65%, and the level you choose will depend on the size of the grow tent. That said, the larger your tent, the higher the moisture levels you should set.

The ideal place to install the humidifier is the bottom to prevent the mist from spraying directly on grow lights if you are using some.

A humidifier is an easy way out; however, you must keep track of the moisture levels as leaving it on the highest setting could bring about too much moisture in your grow tent. This can adversely affect your plants and cause more harm than good.

Look for a humidifier with a built-in humidistat; that way, you can activate the auto-shut feature to switch it off once the desired moisture levels have been achieved. Ultimately, this will help control the temperature, airflow, and moisture.

3. Utilize Propagators

Propagators can come in handy to help you germinate seedlings and attain a higher success rate. This is because propagators raise the humidity considerably, speeding up the germination and growth process [2].

Some of the types you can use are polyethylene or glass cover sheets to keep your seeds moist during the germination stage. During this stage, the optimal humidity levels will start the plant with healthy roots systems, which are essential for growth and development.

4. Set Water Trays Near Air Holes

When increasing the humidity of your grow tent, all you are trying to do is raise the moisture levels in the indoor environment. One of the ways you can do this is by setting trays of water near air holes.

As the air blows into the grow tent, it carries mists of water from the trays increasing the moisture levels in the tent. This method may not help much, but if you have a small grow tent that does not warrant the installation of a humidifier, then this can be a great option.

5. Cut The Number of Fluorescent Lights

One of the ways of maintaining or increasing humidity in grow tents is by controlling the temperatures. Surprisingly, fluorescent lights emit heat which in turn dries out the indoor environment [3].

Removing a few tubes can surprisingly increase humidity in the grow tent, especially when the plants are young. Nonetheless, the plants do not need much light in the early developmental stages and can do with just a few tubes.

6. Reduce The Fan Speed to Minimum

Extraction fans are essential in grow tents as they help to control the humidity levels. However, if they are running at high speeds, they may result in excessive removal of essential moisture, dropping the humidity levels significantly.

This is why it is vital to reduce the fan speeds and the amount of moisture driven out. That way, the grow tent has an adequate concentration of moisture but is also well-ventilated to ensure proper airflow.

If you have several fans in your grow tent, you can uninstall some and keep a few, enough for ventilation. Ensure you distribute them evenly to ensure proper ventilation around the grow tent while preventing excess moisture removal from your plants’ leaves.

7. Utilize Water Spray Bottles

One of the handy tools you should have as an indoor plant grower is a simple water bottle. It is essential to spray your plants once in a while, most notably when the temperatures are high. The idea is to cool off your plants’ leaves while providing them with essential moisture.

Another way you can utilize your water bottle is by spraying the interior walls of the grow tent. The water will then evaporate from the walls and concentrate moisture in the tent. That will increase humidity significantly and meet your plants’ needs.

8. Control The Surrounding Temperature

It’s clear that a reduction in temperature can significantly increase humidity. This is based on the fact that cooler air is denser owing to the higher moisture content. Therefore, when you reduce the temperature in the surrounding, you facilitate an increase in humidity.

You can do this by dropping the intensity of ultraviolet light to help increase water vapor in the grow tent. But do this only when the light is adequate to facilitate water evaporation which will, in turn, increase indoor humidity levels.

You can also utilize a swamp cooler to lower the temperature in the grow tent and help increase the humidity levels. It works well when the humidity levels are down and when the temperatures are high.

Lastly, you can control the temperature levels by installing an air conditioner in the tent. You can use it to balance humidity and temperature levels by reducing the heater’s settings and increasing the air conditioning settings.

This will reduce the amount of moisture extracted while ensuring adequate ventilation in the grow tent. But, you have to keep track of the temperature and humidity levels to ensure they do not go out of hand.

The Bottom Line

These methods of increasing humidity in grow tents can come in handy to ensure optimal conditions for indoor plants. You can choose the simple DIY methods or invest in humidity-control devices, as long as you have the right balance between humidity and temperature.

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