How To Raise Humidity in Grow Tent

Eric St-Cyr | March 09, 2023 | 9 MIN READ

The biggest worry for any indoor grower is seeing their plants begin to dry out. It's game over for you if we add problems like stressed-out plants and underdeveloped plant roots to the mix. Guess what? Low humidity in the grow room is the fundamental cause of all these problems.

You could observe the leaves getting extremely dry, curling, or nutritional burn if you have low-humidity herbs. Fortunately, regulating humidity in grow tent setups is not too complicated.

Adaptability with your humidity settings is essential since your plants' humidity needs might alter as they mature. We'll examine what occurs when your humidity levels are too low, the heat is too high and what your humidity levels should be. The following article explains some of the most efficient techniques and options to regulate humidity in your grow tent.

When you learn how to control all the tiny, complicated moving pieces, such as light, temperature, ventilation, and humidity, you'll be able to grow your plants in grow tents with fantastic success.


Why is Humidity Level Important for Plant Growth?

In a grow room or tent, humidity is excellent since it means your plants are healthy and have access to enough water to thrive. Different degrees of humidity are required at different times in a plant's life to properly seed, veg, and bloom.

Photosynthesis requires humidity to be achievable. Since Anthurium can only absorb a little humidity and evaporates less water than other plants, maintaining a proper humidity level surrounding the plant is even more crucial than most other crops.

The stomata will close if the plant loses too much water, ending photosynthesis. No more CO2 can be absorbed if this occurs, even though photosynthesis needs CO2 to continue.

A plant cannot make water evaporate or extract nutrients from the soil when relative humidity levels are too high or there is insufficient air circulation.

The result is that a plant finally rots when it happens frequently. A plant's transpiration rates rise in warm environments with low relative humidity levels, which minimizes the requirement for fertilizer application by a gardener.

Related: How to Add CO2 to Your Grow Tent?

What are Relative and Absolute Humidity?

Absolute and relative humidity indicates the amount of water vapor in the air, but they are very different. Particular techniques are used to measure humidity, and each technique has a different use. Let's get a better understanding of relative and absolute humidity further.

Relative Humidity

Relative humidity is a measure of the percentage of water vapor in the air compared to its saturation level at a certain temperature. It is expressed as a percentage and is based on the ratio of actual water vapor pressure to saturated water vapor pressure.

It represents a portion of the potential moisture in the air. Unless the air temperature accompanies the relative humidity measurement, it is impossible to determine the amount of moisture in the air.

The relative humidity falls as the temperature rises if the moisture content of the air stays constant and vice versa.

Absolute Humidity

The air's density or vapor concentration is known as absolute humidity. It symbolizes the weight of vaporized water per kilogram of dry (moisture-free) air in a humid environment.

The mass of the water vapor in the air is used to calculate the absolute humidity. Both kilograms and pounds of water vapor can be used to express it.

The volume of the water vapor is then taken into account. Typically, this density measurement is represented in grams per cubic meter or pounds per cubic foot. In other words, absolute humidity calculates the water vapor's density.

Why Low Humidity is a Bad Idea

The plants develop poorly when the humidity within the grow tent is reduced. As a result, the plants are unable to develop and ultimately perish.

Additionally, less humidity causes plants' leaves to dry up more quickly. Numerous insects, including mites, molds, and others, would take advantage of this circumstance and attack the plants.

The only way the roots get absorbed by the surface is in the case of less than enough humidity. This results in the leaves drying out since they lack sufficient nutrients.

Why Low Humidity is a Bad Idea

Essential PH Levels for Every Plant Stage of Growth

You probably already know that all plants need nutrients to flourish properly. In addition to the nutrients and minerals calcium, magnesium, iron, copper, and a bunch more, they need the macronutrients nitrogen, phosphorus, and potassium. Plants will suffer from deficits and other major health issues if they cannot get these nutrients.

Simple benefits of taking care of and regulating your plants' pH levels include healthier plants that develop more vigorously and, as a result, yield higher harvests. Additionally, you'll ensure that the money and time you invested in fertilizing your plants has been profitable.

You can ensure your plants can absorb all the nutrients you're providing by routinely testing your growing medium's ph. Additionally, you'll be able to identify any pH imbalances early on, reducing the likelihood that you'll experience nutritional deficiencies further on in your bloom.

Read More: How To Clean A Grow Tent.

Ways to Raise Humidity in a Grow Tent

Increasing the levels of humidity is the secret to preventing plants from browning and withering and promoting blooming and growth. Various widely used methods exist to treat the effects of low humidity on plants.

Keep your Grow Tent Clean

It's crucial to keep your grow tent clean if you want to keep elevated humidity levels. Maintaining a clean grow tent is essential to prevent mold or germs, even when using a humidifier.

When you see dirt particles, use a vacuum cleaner around your grow tent to stay clean. Sweeping up stains on the floor of your grow area is also made much easier with a wet/dry vacuum.

To remove any bacteria that could have accumulated on surfaces while you were away caring for your plants, you should also wipe them down with water- or alcohol-based cleansers.

Use a Humidifier

Adding a humidifier is one of the simplest and easiest methods to increase tent humidity, in the grow room.

You can locate the humidifier you're searching for because they come in various sizes, styles, and features.

A grow tent humidifier is crafted to constantly release water vapor in the air and increase moisture levels, producing the most excellent growing environment for indoor plants.

The humidifier present in a grow tent ensures that it manages its operation. This means you can leave it on without any worries.

Ensure your humidifier is operating as needed and isn't producing excessive humidity. Since humidity will change often and cannot be maintained on a routine like watering or lighting, digital models feature sensors that activate the humidifier when it exceeds a set level. Timers for humidifiers should not be utilized since humidity will change frequently.

Place water sources in the grow tent

Placing water sources in the vicinity of your plants will help increase the levels of humidity in your grow tent. You have several solutions to properly do that: 

  1. Water tray: You can place a tray of clean water underneath your plants. As the water evaporates, it will help to increase the humidity in the grow tent.

  2. Wet towels: You can get a few towels and hang them inside the grow tent. As the towels dry, they will release moisture into the air, raising the humidity in the grow tent.

  3. Bucket of water or a wet sponge: You can put a bucket of water or a wet sponge close to an airflow which will help you mist, create lots of moisture, and therefore raise humidity in your grow tent benefiting the various stages of plant growth.

Adjust Fan Speed

The quantity of humidity evaporating from the tent can be momentarily reduced by reducing the extraction fan's settings.

Proper ventilation is necessary to establish an ecosystem where plants may grow and thrive. Grow tents include air vents or holes so the air inside them may be continually changed.

If your tent has fans, turn them on as slowly as possible to avoid making the air inside the tent too dry. If your tent has numerous fans, consider taking off a few to raise the relative humidity.

Additionally, fans provide good air circulation and distribution to your developing plants. At various phases of plant growth, people typically keep their fans running at a moderate speed to save moisture. High-speed fans will cause the air to dry up faster than usual.

Like this, running fans at a fast speed can keep water vapor from condensing on the leaves of your plants so it can't be absorbed. This prevents moisture from getting to the plants, which might lead to dryness and dehydration.

Don't Forget About Grow Lights

Although light only has a minor influence on humidity levels in the various stages of growth of your plants, it's an effect nonetheless.

As plants photosynthesize and use light energy to convert carbon dioxide and water into glucose and oxygen, they release water vapor into the air. This process, called transpiration, can contribute to an increase in humidity in the grow tent.

The amount of heat that they generate can affect the humidity levels. If the grow lights are generating too much heat, they can cause the air inside the grow tent to become warmer and more dry, which can lower the humidity levels. On the other hand, if the grow lights are not generating enough heat, the air inside the grow tent may become cooler and more humid, which can raise the humidity levels.

It's important to keep the temperature and humidity levels in the grow tent within the optimal range for your plants. Too much or too little humidity can have negative effects on plant growth. 

Don't Forget About Grow Lights

Changing Temperature

The air becomes more humid when the temperature within the grow tent drops of some degrees. This temperature drop increases the amount of water vapor available for your plants to absorb and creates lots of moisture which can be good for the growth of plants at a certain stage. Because the stomata are open, your plants won't be able to dry up and will continue to produce energy through the photosynthesis process.

You can regulate the temperature of your grow tent by adjusting the setting on your heater or air conditioner. Additionally, decreasing the intensity of the UV light for your plants slows down water evaporation and helps maintain a comfortable temperature.

If dropping the temperature in your grow tent will bring it outside the ideal range for your plants, try not to. Cold air requires less moisture to reach full saturation, and so decreasing it can raise humidity levels too.

The relationship between temperature and humidity is inverted; the more heat in the air, the more water vapor it will hold. More humidity will gradually envelop the tent in a colder atmosphere.

Lowering the air temperature in your heater or air conditioner causes the hotter, moister air to ascend toward the tent's top while the colder air falls to the bottom. The procedure will make the air more humid.

Combine Mature and Infant Plants

Combining mature plants with baby plants is a simple additional method to increase tent humidity.

To ensure that young plants receive the proper quantity of moisture throughout their most crucial developmental periods, you can group them with larger plants. Just be careful not to overdo it since the younger plants won't be able to obtain the nourishment they need.

The relative humidity in a grow tent will increase as you add more plants since different plants, huge ones, respire more and raise humidity. To guarantee that larger plants receive equal air, light, and nutrients and develop appropriately, don't cram them into small spaces.

The larger plants' respiration results in carbon dioxide and water vapor emission, which feeds the larger plants. To ensure that the plants get a fair share of light and nourishment, it's important to avoid overcrowding them.

Combine Mature and Infant Plants

Add Ventilation

Fans used for extraction or venting are proven to supply developing plants with enough air. Doing this can stop germs and mold from growing within the tent. However, excessive ventilation may prevent mist from condensing for absorption on your plants' surface.

You can raise the relative humidity without creating other problems within the tent if you can decrease the air circulation brought on by your extraction fan.

Therefore, enough ventilation is necessary to maintain appropriate RH values. You may use a stand-up fan, an extractor fan, or a clip-on fan to make sure there is adequate air moving about. It's crucial to consider the geometry of where you put the fans for ideal humidity level in the grow tent.

The Takeaway!

Try these suggestions to help increase the humidity in grow tents. The most crucial thing, though, is to ensure that your plants are receiving adequate water. Their ability to endure dry air improves as they consume more water.

Getting the right grow tents is also essential for optimal plant growth. Find the best Grow tents at Grow Supplies.

To learn more about grow tents, you can always check out Grow Tent Ventilation Guide for thorough directions.


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