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How To Lower Humidity In A Grow Tent


High humidity can be a grower’s nightmare, leading to mold, mildew, and unhealthy plant growth. Here’s how you can maintain optimal humidity levels within your grow tent.

Improve Ventilation:

Install exhaust fans at the top of your tent to expel warm, moist air, and place intake fans lower to bring in cool, dry air, creating an effective air exchange system. Ensure fans are appropriately sized for your tent’s volume. Regularly check and maintain the fans to ensure optimal performance and air circulation around all plants, preventing stagnant air and hotspots that contribute to humidity issues.

Here are some of the top of the line exhaust fans for grow tents:

  1. AC Infinity CLOUDLINE T6: Rated highly for its CFM, quietness, and quality. It’s an inline fan known for its powerful air intake and outtake​​.
  2. Hurricane Classic 6” Clip Fan: A top-rated clip-on fan, praised for its CFM, electricity consumption, and quiet operation. It’s ideal for small spaces and targeted air circulation​​.
  3. Hurricane Supreme Oscillating Fan: This is a highly regarded oscillating fan known for its CFM rating and quality. It’s designed to provide air circulation throughout the plant canopy​​.
  4. Vivosun Inline Duct Booster Fan: Known as the best axial fan with good CFM and quiet operation. It’s used for boosting air in larger tents or rooms that require extensive ventilation​​.

Use a Dehumidifier:

A dehumidifier is crucial for controlling excess moisture in a grow tent, ensuring a healthy plant environment. Choose a size based on your tent’s dimensions and the specific humidity needs of your plants. A properly sized dehumidifier ensures effective moisture removal without overworking the unit or underperforming in maintaining the desired humidity levels. Consider the capacity, energy efficiency, and the specific features that match your growing conditions for optimal results.

  1. Pohl Schmitt (225 sq ft): Best cheap option for 4×4 grow tents.
  2. Eva-dry: Best small petite dehumidifier, ideal for 2×4 grow tents.
  3. VIVOSUN: Best mini dehumidifier suitable for 3×3 grow tents.
  4. Pro Breeze: A good choice for 4×4 grow tents.
  5. Ivation: Thermo-Electric Dehumidifier, effective for larger 5×5 grow tents

Absorb Moisture:

Products like silica gel can absorb moisture from the air. Place these around your tent for an added humidity control measure.

Adjust Watering Schedule:

Overwatering plants can significantly increase humidity levels as the excess water evaporates into the air. To mitigate this, water your plants only when necessary, using just enough to meet their needs. Monitor soil moisture closely and adjust your watering schedule accordingly. Reducing the quantity of water used not only prevents root issues from overwatering but also minimizes unnecessary evaporation, helping maintain optimal humidity levels in your grow tent.

Maintain Cooler Temperatures:

Warm air holds more moisture, so lowering the temperature in your grow tent can help reduce humidity. The ideal temperature range for most plants is between 70°F and 80°F (21°C to 26°C) during the day and slightly cooler at night. By keeping within this range, you can manage moisture levels and ensure a conducive environment for plant growth.


Controlling humidity is crucial for a healthy and fruitful grow. Implement these strategies to maintain an ideal growing environment and ensure the success of your indoor garden. Happy growing!

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