Humidity is the amount of water vapor in the air. When it comes to growing plants, humidity is important because it affects the plant’s ability to transpire. Did you know that transpiration is the process of water vapor leaving a plant and entering the air? If the humidity is too high, transpiration will be inhibited and your plants will not grow as well as they could. In this article, you will learn how to lower humidity and control it within your grow tent for optimal plant growth!
If you are interested in Humidity in Your Grow Tent you can also be interested in indoor hydroponic systems to help you easily start growing plants and grow tomatoes all year round. Our top articles: Our Picks for the 5 Grow Tent Kits, Picks for the 5 Aeroponics Systems, Our Picks for the 5 Hydroponic Bucket Systems with Buyer’s Guides, and Our Picks for the 5 best indoor vertical Garden, and Led Grow Lights for an indoor plant, and The Best Hydroponic Tower for Indoor Garden.
Why does the humidity rise in the grow tent?
The humidity inside a grow tent can increase due to several factors. Firstly, watering the plants can increase the humidity in the surrounding environment. Secondly, if you use a humidifier in your grow room, it can also contribute to the rise in humidity. Lastly, certain plants, such as tropical plants that thrive in high humidity, can release water vapor into the air and contribute to increased humidity levels.
Increased Transpiration
One of the benefits of lower humidity is that it will help your plants transpire more. Water vapor leaves the leaves of a plant through transpiration. This vapor is then replaced by water from the roots, which helps to circulate nutrients and keep the plant healthy. When transpiration occurs, it cools the plant and helps to regulate its temperature. In addition, transpiration helps to prevent moisture stress in plants and can improve their resistance to diseases.
Open Water Surfaces
Another effective way to lower the humidity in your grow room is to expose water surfaces. Doing this allows air to circulate, and can be done by adding a small fan or opening a window. By doing this, you will allow the evaporating water to escape and the dry air to enter. This will help to lower the overall humidity in the room.

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Too Humid Outside Environment
If the environment outside of your grow room is too humid, there are a few things you can do to combat this. One is to use an air conditioner or dehumidifier in the space. The best way to get rid of moisture from the air is to use a dehumidifier. This will help remove some of the dampness from the air and reduce overall humidity levels. A fan may also be used to move the air around and aid in its drying out. Finally, you can try opening a window or door to let some of the moist air escape.

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Overwatering
Overwatering is one of the most frequent reasons for high humidity in a grow room. When you water your plants, water evaporates into the air and raises the humidity level. If you are watering too often, or if you are using too much water, this can lead to a build-up of moisture in the air. If this happens, try to avoid overwatering your plants by only watering them when necessary and using as little water as feasible.
How do I know if my grow room is too humid?
If your grow room feels damp or sticky, the humidity levels are probably high. too high. A hygrometer will precisely tell you the humidity level in your grow room. Most plants do best in an environment with a relative humidity of 40-60%. If the water level is higher than this, you’ll need to do something about it.
What are the effects of high humidity on plants? (Top 11 indicators)?
If the humidity in your grow room is too high, it can harm your plants. Transpiration is one of the plant’s cooling systems, so if it isn’t working properly, your plant won’t be able to cool down. This can lead to heat stress and can damage the plant. In addition, high humidity can promote the growth of mold and mildew on the plant’s leaves, which can cause disease. Finally, high humidity can make it difficult for the plant to take up nutrients, which can stunt its growth.
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1. Bud rot
One of the most serious problems that can be caused by high humidity is bud rot. Bud rot is a fungal disease that attacks the flowers of a plant. It is a fungus that attacks and destroys cannabis buds, which can result in them turning brown and dying. It spreads rapidly throughout a crop. If you suspect that your plants have bud rot, it is important to remove the affected buds immediately and to lower the humidity in your grow room.
2. Powdery mildew
Powdery mildew is another condition that can be induced by high humidity, powdery mildew is a fungus that attacks the leaves of plants. The leaves may turn yellow or brown, and the plant may die as a result of powdery mildew.
3. Mildews
Mildews are a type of fungus that may infect the leaves of plants. They can make the leaves yellow or brown, and if not treated, they can eventually kill the plant.
4. Fungi
Fungi are a type of organism that may live on the leaves of plants. They can cause leaves to become yellow or brown, and they can eventually kill the plant.
5. Bacteria
Bacteria are a type of microorganism that can grow on the leaves of plants. Cabbage maggots feed on the leaves of your plants, causing them to turn yellow or brown and in some cases killing them.
6. Nutrient deficiencies
Another problem that can be caused by high humidity is nutrient deficiencies. When the air is too moist, it can prevent the plant from taking up nutrients properly. If this continues, the plant will not grow as tall as it should, and its leaves will begin to turn yellow.
7. Pests & Diseases
High humidity can also create an ideal environment for pests and diseases. In humid conditions, insects and fungi thrive, so keeping the humidity in your grow room under control is critical to avoid infestations. In addition, high humidity can make plants more susceptible to diseases.

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8. Metabolism Impact
High humidity can also impact the metabolism of your plants. In humid conditions, the plant’s stomata will close to prevent water loss. This can cause the plant to use less oxygen and produce more carbon dioxide. As a result, the plant’s growth can be stunted.
9. Restriction Of Growth
If the humidity in your grow room is high, it will limit the growth of your plants. High humidity can inhibit transpiration and prevent the plant from cooling itself. This can lead to heat stress and can damage the plant. In addition, high humidity can promote the growth of mold and mildew on the plant’s leaves, which can cause disease. Finally, high humidity can make it difficult for the plant to take up nutrients, which can stunt its growth.
10. Inadequate Water Consumption
One of the most common problems that can be caused by high humidity is inadequate water consumption. When the air is too moist, it can prevent the plant from taking up water properly. Foliage can become loose and crinkled, and the leaves may yellow and wilt. Problems With FloweringHigh humidity can also cause problems with flowering. Flowers that are exposed to too much moisture can become moldy and rotten. Furthermore, excessive humidity might cause the flowers to drop off before they are ready. Fruit & Vegetable RotAnother problem that can be caused by high humidity is fruit and vegetable rot. When fruits or vegetables are exposed to too much moisture, they can start to rot and decay. This can lead to spoilage and waste.
11. Poor Plant Yield
High humidity can also lead to poor plant yield. When the air is too moist, it can prevent the plant from taking up nutrients properly. Rainfall, wind, heat, and drought can all impact a crop’s growth. Sometimes these natural disasters are beyond human control, but when they’re not, planting in the wrong place or too early may lead to stunted growth and reduced yields.
The Best Ways How to Control Humidity in Grow Tent
There are a few different ways that you can control the humidity in your grow room. You can use a humidifier, dehumidifier, or even fans to help get the humidity where you want it.
Ventilation of grow tent humidity control
Controlling humidity is best done through ventilation.By opening up the windows and doors, you can allow fresh air to circulate and help to remove excess moisture from the air.

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Dehumidifiers how to control humidity in grow tent
Another way to control humidity is with a dehumidifier. Dehumidifiers improve air quality by lowering the humidity in your grow room to an ideal level.
Humidifiers
If the air in your grow room is dry, use a humidifier to add moisture back into the air. By keeping the humidity at an ideal level, you can prevent problems such as wilting, yellowing of the leaves, and stunted growth.
Fans for grow tent humidity control
Fans can be used to control the humidity in your grow room. By circulating the air, fans can help to remove excess moisture from the air and keep the humidity at a desirable level.
Watering
Another way to control humidity is through watering. By ensuring that your plants are properly watered, you can help to prevent problems such as wilting and yellowing of the leaves.
Misting
If you live in an area with little rainfall, you may need to spray your plants with water often. Misting helps to add moisture back into the air and can keep the humidity at an ideal level for your plants.
What is the difference between absolute humidity and relative humidity?
The relative humidity is the percentage of the water content in the air that it could possibly hold. The phrase absolute humidity is less frequent: it refers to the total quantity of water vapor in the air in g/m3. This, too, is determined by temperature.
How to Use a Hygrometer to Monitor Indoor Humidity?
To get an accurate reading of the humidity in your home, you need to use a hygrometer. A hygrometer is an instrument that measures the amount of water vapor in the air.
Before you start using your hygrometer, you’ll need to calibrate it. To do this, place the hygrometer in a container of water and wait for 24 hours. After 24 hours, check the reading on the hygrometer and adjust it accordingly.
After calibrating your hygrometer, you can place it in your grow room to monitor the humidity levels. It is important to check the readings regularly to ensure that the humidity levels are staying at an optimal level.
If you notice that the humidity levels are too high or too low, you can take steps to adjust the level accordingly. By keeping the humidity at an ideal level, you can prevent problems such as wilting, yellowing of the leaves, and stunted growth.

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What Is The Ideal Humidity Range?
Most plants grow best in a humidity range of 40% to 60%. However, some plants may prefer a higher or lower humidity level. Before you set the humidity level, it’s a good idea to learn your plants’ specific requirements.
- Seedling Stage – 65-70% Humidity Level
- Vegetative Stage – 60-65% Humidity Level
- Early Flowering Stage – 40-50% Humidity Level
- Flowering Stage – 40-50% Humidity Level
- Late Flowering Stage – 45-50% Humidity Level
- Fruiting Stage – 50-60% Humidity Level
- Harvesting/Drying: 30-40%
BONUS: Ways to lower the humidity in a grow tent (Top 12 Tips)
If the humidity in your grow tent is too high, there are a few things you can do to lower it.
1. Say No To Overwatering!
One of the main causes of high humidity in a grow tent is overwatering. When you water your plants too much, the water will evaporate and raise the humidity levels.
It’s important to water your plants only when they need it. You can tell when they need watering by checking the soil. If it is dry, then it’s time to water them.
If you’re not sure how often to water your plants, check out our guide on watering schedules here.
2. DampRid Moisture Absorber
Another way to lower the humidity in your grow tent is to use a moisture absorber. DampRid is a type of moisture absorber that can be used to take away extra water from the air.
DampRid comes in a variety of forms, including desiccants, gel, and liquid. You can purchase DampRid online or at most hardware stores.
To use DampRid, simply place it in your grow tent and allow it to do its job. For best results, you should check the DampRid regularly and replenish it as needed.

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3. Create Air Holes
Air holes are one more method to decrease the humidity in your grow tent. By creating air holes, you can allow the excess moisture to escape from your grow tent.
To create air holes, simply drill or punch small holes in the top and sides of your grow tent. BMake sure the holes are placed near the plants so they can get adequate ventilation. Also, make sure your grow room’s air vents are open so that moist air may escape.
4. Use Foam Isolation
If you’re growing plants in a grow tent, you can use foam isolation to lower the humidity. Foam isolation is a type of material that helps to block out moisture.
You can purchase foam isolation online or at most hardware stores. To use foam isolation, simply place it around the perimeter of your grow tent.
By creating a barrier between your grow tent and the outside air, you will trap in humidity and prevent it from escaping. As a result, the humidity levels in your grow tent will be lowered.
5. Lower the Temperature
Lowering the temperature is another approach to reduce the humidity in your grow tent. When the temperature is high, the air can retain more moisture. As a result, lowering the temperature will aid in reducing moisture levels in the air. A fan or an air conditioner may be used to decrease the temperature within your grow tent. You can also open the door or window to let in cooler air.
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6. Defoliate Plants
If the humidity in your grow tent is still too high, you may need to defoliate your plants. Defoliation is removing leaves from a plant and will aid in lowering the humidity levels of your grow space.This is because the leaves are responsible for transpiration, which is a process that releases moisture into the air.
To defoliate your plants, simply remove the leaves using either your hands or a pair of scissors. Be sure to do this carefully so as not to damage the plant.
After you have removed the leaves, you can dispose of them in the compost bin.
7. Grow Bulbs
If you’re looking for a natural way to lower the humidity in your grow tent, you can try growing bulbs. By absorbing moisture from the air, bulbs like daffodils and tulips can help to lower the humidity in your grow room. To use bulbs to lower the humidity, simply plant them in pots and place them in your grow tent.
Be sure to water the bulbs regularly so that they can continue to absorb moisture from the air.
8. Bi-carbonate Soda
Additionally, bi-carbonate soda works well to lower the humidity in your grow tent. Bi-carbonate soda is a type of baking soda that helps to absorb moisture from the air.
To use bi-carbonate soda, simply place it in a bowl and place it in your grow tent. For best results, you should check the bi-carbonate soda regularly and replenish it as needed.
9. Enough Ventilation
The most critical aspect of humidity management in your grow tent is to provide enough ventilation. Without adequate ventilation, the air will become stagnant and humid.
As a result, your plants will be more susceptible to fungal diseases. To ensure that there is enough ventilation in your grow tent, you should open the door or window for at least 30 minutes each day.
You should also make sure that the air vents in your grow room are open so that the humid air can escape.
10. Eliminate Stagnant Water
Another way to control the humidity in your grow tent is to eliminate stagnant water. If your grow tent is not well ventilated, the stagnant water can create a breeding ground for bacteria and fungi, which can increase the humidity levels. To eliminate stagnant water, you should remove any standing water from your grow room.
You should also change the water in your plants regularly and clean out any dirty pots.
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11. Use Water-Absorbent Soil
If you’re looking to lower the humidity in your grow tent, water-absorbent soil can help. This type of soil helps by absorbing moisture from the air, which then lowers the humidity levels in your space. planting your plants in water-absorbent soil is easy – simply put them in it!
You can find water-absorbent soil at most garden stores or online.
12. Restrict Plant Density
If the humidity levels in your grow room are still too high, you may need to reduce the number of plants that are growing in that area. The more plants that are growing in an area, the higher the humidity levels will be. To restrict plant density, you should space your plants further apart.
You can also try to grow fewer plants in your grow room.
13. Get an air conditioner
If the humidity in your grow room is proving to be a struggle, an air conditioner may be necessary. Air conditioners work by removing moisture from the air, which can help lower the humidity levels in your space. Air conditioners can be expensive, so be sure to shop around for the best deal.
You can also try renting an air conditioner if you don’t want to purchase one outright.

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Things to Do to Avoid Further Raise in Humidity
- Avoid over-watering your plants
- Don’t place your grow room near a water source
- Make sure the temperature in your grow room is cool
- Insulate Your Grow Space from Outside
- Run an exhaust fan to circulate the air in your grow room
- Use Soil That Absorbs Vapor
- Don’t Depend on One-dimensional Ventilation
- Use The Right Size of AC Units
- Use a dehumidifier to remove moisture from the air
- Keep an Eye on Your Humidity Level
By following these tips, you can effectively lower the humidity in your grow tent and create a more hospitable environment for your plants. By creating an optimal growing environment, you’ll be able to produce healthier and more vibrant plants. What are some good techniques for lowering the humidity in a grow tent? Leave a remark below with any suggestions you may have!
How to lower humidity in grow tent?
Here are some ways to lower the humidity inside a grow tent:
- Improve ventilation: Good airflow can help reduce humidity levels in a grow tent. Ensure to install an exhaust fan and a circulation fan to maintain proper air circulation.
- Adjust temperature: Lowering the temperature inside the grow tent can also help reduce humidity. Try to maintain a temperature range of 68-77°F.
- Use a dehumidifier: A dehumidifier is a device that removes moisture from the air. If your grow tent has high humidity levels, consider using a dehumidifier to lower them.
- Avoid overwatering: Overwatering can increase humidity levels inside a grow tent. Make sure to water your plants only when necessary and avoid watering during periods of high humidity.
- Choose plants that thrive in low humidity: If you are still struggling to lower humidity levels, consider growing plants that are well-suited for low-humidity environments.
Summing Up about lowering humidity in grow tent
High humidity levels can have some negative consequences for your plants, including the development of mold, leaf curling, and stunted growth.
- The ideal humidity range for cannabis cultivation is between 40-60%.
- There are many ways to lower the humidity in your grow room, including using water-absorbent soil, spacing your plants further apart, and getting an air conditioner.
- By following these tips, you can create a more hospitable environment for your plants and produce healthier and more vibrant plants.
In summary, there are several ways to lower humidity in a grow tent. These include improving ventilation, adjusting temperature, using a dehumidifier, avoiding overwatering, and choosing plants that thrive in low humidity environments. By implementing these strategies, you can create a healthy and optimal environment for your plants to grow and flourish.

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FAQ
How do lower humidity in a tent when the grow lights are off?
The best way to lower the humidity in your grow tent when the lights are off is to use a fan. By circulating the air, you can help to remove the humid air and replace it with drier air.
How to lower humidity in a tent when drying?
The best way to lower the humidity in your grow tent when drying is to use a fan. By circulating the air, you can help to remove the humid air and replace it with drier air.
What size dehumidifier is needed?
The size of the dehumidifier you need will depend on the size of your grow room. For a small grow room, you can use a portable dehumidifier.
For a larger grow room, you’ll need to purchase an industrial-sized dehumidifier.
Room Size 400 Sq. Ft. 600 Sq. Ft. Relative Humidity Level
50% to 60% 20-Pint 25-Pint
60% to 70% 20-Pint 30-Pint
70% to 80% 25-Pint 35-Pint
80% to 90% 30-Pint 40-Pint
What Are The Cheap Ways To Lower Humidity In Grow Tent?
The cheapest way to lower the humidity in your grow tent is to use a fan. Fans help to circulate the air and remove humid air from the grow room.
You can also try using water-absorbent soil or restricting plant density. These methods can help to lower the humidity in your grow room without breaking the bank.

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