Grow Tent

How to Lower Humidity in Grow Tent with/without Dehumidifier

How to Lower Humidity in Grow Tent

How to Lower Humidity in Grow Tent [Budget-Wise Choices]

As indoor growers, we both know maintaining the right humidity level in the grow tent is crucial for cannabis growing. Excess humidity in a grow tent can lead to mold, mildew, and other issues that can harm weed plants. Once the grow tent humidity crosses the borderline that your plants can handle, how to lower humidity in grow tent becomes an issue. In this article, we will explore effective methods to lower humidity in a grow tent, including both using a dehumidifier and not using it. 

Table of Contents

What’s the Ideal Grow Tent Temp & Humidity 

Before anything else, it’s essential to know what’s the best grow tent temp and humidity level for your plants. For different stages of plant growth, the preference differs as well. To save you time, we prepared a grow room temp and humidity chart that illustrates the ideal metric for each stage.

humidity and temperature for different stages of plant

Once the humidity goes beyond the suggested level, what will happen? Possibly, you’ll encounter the following situations:

  • Mold and Mildew Growth: Excess moisture in the air creates a favorable environment for mold and mildew. These fungi can spread throughout your grow tent, damaging plants, and creating moldy weed.

moldy weed

  • Pest Infestations: High humidity can attract pests such as spider mites, fungus gnats, and whiteflies. These pests thrive in humid conditions and can quickly infest your plants, causing damage and inhibiting growth.
  • Reduced Nutrient Uptake: High humidity can affect the plant's ability to absorb nutrients effectively. It can lead to Cal-Mag deficiency, stunted growth, and overall weaker plants.
  • Root Rot: Excessive grow tent humidity can saturate the growing medium, leading to poor oxygenation and root rot.
  • Flowering Issues: High humidity during the flowering stage can hinder proper pollination and the development of healthy flowers. It may lead to poor yields, malformed buds, or decreased potency.

Bet you don’t want to experience any of these, so, how to lower humidity in grow tent? 

How to Lower Humidity in Grow Tent

Use a Dehumidifier Inside Your Grow Tent

Frankly speaking, the most effective and effortless way to reduce humidity is by using a dehumidifier. The only downside lies in the cost. 

A dehumidifier is a device that extracts excess moisture from the air, helping to reduce humidity levels in the grow tent. It works by pulling in air, cooling it, and collecting the moisture before releasing the drier air back into the environment. By using a dehumidifier, you are guaranteed precise humidity control and improved air circulation. 

However, if you don’t want to invest in a commercial dehumidifier, there are plenty of ways to lower humidity in grow tent without spending too much. Let’s see how to lower humidity in grow tent without dehumidifier. 

Prevent Overwatering Your Plants

To decrease humidity levels in your grow tent, it is quite important to avoid overwatering your plants. Overwatering leads to an excess of water, which can elevate humidity levels beyond the appropriate range. Additionally, saturated soil can result in extra water in seed starting trays, further contributing to increased humidity levels. To avoid overwatering cannabis, simply water according to plant needs, not a schedule. 

Check the Plant Density to Improve Ventilation

Plant density has a significant impact on the humidity levels in your grow tent. As plants release carbon dioxide, the temperature within the tent rises, leading to moisture buildup and increased grow tent humidity. You may want to reduce the number of plants for proper air circulation and carbon dioxide distribution. If removing plants is not an option, consider relocating only those with large leaves. 

cannabis density in a grow room

Remove Stagnant Water

You may not realize, but stagnant water on the ground can contribute to excessive humidity. What’s worse, when water remains stagnant, molecular oxygen is reduced, providing an environment for bacteria to thrive. By removing still water, you can not only lower humidity in grow tent but also prevent bacteria from growing. 

Enhance Ventilation with Inline Fans

Improving ventilation by adding inline fans is an effective way to increase airflow in your grow tent and lower humidity. By facilitating airflow, inline fans assist in regulating temperature and humidity levels. They can help remove excess heat and moisture from the grow tent, preventing heat stress and promoting optimal growth.

Spider Farmer Inline Fan Kits

Don’t know what to choose? Check the Spider Farmer ventilation systems!

Spider Farmer® 4-Inch 205 CFM Inline Fan with Smart Controller

【QUIET & POWERFUL】 Mixed flow design combined with an EC motor that powers high-quality impellers makes this fan truly energy

Spider Farmer® 6-Inch Inline Fan Kits 402CFM with Smart Controller Carbon Filter & Ducting Combo

The Spider Farmer Inline fan & carbon filters effectively remove unwanted odors, ideal for use in grow tents or enclosed grow areas. The Carbon Filters purify and filter out molds, spores, dust, pollen, odors, and other harmful particles. The temperature and humidity controller automates airflow, maintaining optimal growing conditions for better yields and healthier plants.

Spider Farmer®4-Inch 205CFM Inline Fan with Smart Controller, Carbon Filter & Ducting Combo

The Spider Farmer Inline fan & carbon filters effectively remove unwanted odors, ideal for use in grow tents or enclosed grow areas. The Carbon Filters purify and filter out molds, spores, dust, pollen, odors, and other harmful particles. The temperature and humidity controller automates airflow, maintaining optimal growing conditions for better yields and healthier plants. Package includes: 1pc 4-Inch inline fan, 1pc 4-inch carbon filter, 1xprogrammable controller, 1xpre-filter, 1xducting, 2xduct filter vent cover, 2xmagic straps, 2xnormal strapes, 3xclamps

Alternatively, you can open a window to facilitate the removal of moisture from the grow tent, but you should ensure that the intake air has lower relative humidity than the air inside the tent.

Create Air Holes

Regulating the flow of air by creating wider holes in your grow tent also helps to decrease humidity. This technique allows for increased air intake compared to air outflow. However, it is essential to be cautious and prevent unwanted light leaks from entering the tent.

Consider Using an Air Conditioner

Using an air conditioner in your grow tent helps cool the air and effectively lowers humidity levels. The compression and gas processes of an air conditioner remove heat from the air, resulting in condensation and moisture removal. 

Insulate and Seal Your Grow Tent

Proper insulation and sealing of your grow tent can aid in controlling humidity. Why? Using foam insulation helps create a barrier between the outside environment and the tent to prevent external factors from affecting the humidity levels inside. Insulating and sealing the tent properly ensures a more controlled environment for your plants.

Choose Grow Lights Wisely

The choice of grow lights can impact the temperature inside the grow tent and, consequently, the humidity levels. Opt for LED grow lights that are proven to emit less heat to avoid raising the temperature excessively. If the grow tent becomes warm, consider turning off the lights temporarily to allow for a temperature drop. 

spider farmer sf1000 led grow light

The Spider Farmer SF1000 is an exceptional LED grow light that stands out for its low heat emission and energy-saving features. Designed specifically for indoor gardening, this full-spectrum LED grow light utilizes advanced cooling mechanisms and heat sinks to dissipate heat effectively, keeping the temperature at optimal levels for plant growth. Therefore, you won’t have to worry about triggering excessive humidity in the grow tent when applying Spider Farmer SF1000. 

Utilize Absorbent Soil

The type of soil you use can play a role in reducing humidity levels in the grow tent. Choose soil that has good water retention properties, such as sandy soil. Sandy soil minimizes evaporation rates and surface water accumulation. Alternatively, you can incorporate soil amendments like perlite. Another option is using lime or baking soda, which can provide similar benefits to sandy soil. 

Consider Defoliating Your Plants

If you notice high humidity levels in your grow tent, particularly caused by plants with large leaves, consider defoliating some of the leaves. This budget-friendly technique helps prevent humidity from exceeding the recommended levels and allows for better airflow within the tent.

Defoliating cannabis

Wrap up

No need to stress the importance of a proper humidity level in your grow room. Overwatering, inadequate ventilation, and heat generated by grow lights can all contribute to high humidity levels. Fortunately, by implementing effective strategies such as using dehumidifiers, proper ventilation, and controlling watering practices, you can create an ideal environment for your cannabis. 

FAQs about How to Lower Humidity in Grow Tent

  • Do grow lights lower humidity?

No, grow lights themselves do not directly lower humidity in a grow tent. However, they can indirectly affect humidity levels. Grow lights generate heat, and if the heat is not properly managed, it can increase the temperature in the grow tent, potentially leading to higher humidity. 

  • What is the ideal humidity in a grow tent?

The ideal humidity in a grow tent depends on the specific stage of plant growth. Generally, during the vegetative stage, a humidity range of 45% to 55% is recommended. In the flowering stage, it is advisable to lower the humidity to around 35% to 45% to prevent issues such as mold or bud rot.

  • Do fans help with humidity in grow tent?

Yes, fans can help with humidity control in a grow tent. Fans create air movement and promote airflow, which helps to prevent stagnant air and reduce humidity. The increased airflow helps to disperse moisture and prevent it from accumulating in the grow tent. Additionally, fans can aid in maintaining a more consistent temperature throughout the growing area, which indirectly contributes to managing humidity levels.

  • How do I lower the humidity in my habitat?

To lower humidity in a habitat, such as a grow tent, several methods can be employed:

  1. Use a dehumidifier: A dehumidifier is a device designed to remove excess moisture from the air. It can effectively reduce humidity levels in a controlled environment like a grow tent.
  2. Improve ventilation: Proper airflow and ventilation are crucial for humidity control. Increase the airflow by using fans or adding vents to facilitate the exchange of air, allowing moisture to escape.
  3. Avoid overwatering your weed plants: Overwatering can contribute to high humidity. Ensure plants receive the appropriate amount of water based on their needs to avoid excess moisture in the grow tent.
  4. Use humidity packs or desiccants: Humidity packs or desiccants can help absorb excess moisture in the air and maintain a more balanced humidity level.
  5. Monitor and adjust the temperature: Higher temperatures can increase humidity levels. Maintaining an optimal temperature range can aid in controlling humidity.

About Ciki

Ciki has been navigating the digital world of SEO for over 3 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.

One thought on “How to Lower Humidity in Grow Tent with/without Dehumidifier

  1. bgardner951 says:

    Thanks for the knowledge it was very helpful

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