How Often To Run Exhaust Fan in Grow Tent- Ultimate Guide

(Last Updated On: April 20, 2021)

Owning a grow tent may result in a positive economic leap in your life. To some, it is also a platform for research. Therefore, it would be best if you used that grow tent responsibly for you to experience some underlying benefits.

The grow tent should have exhaust fans to enhance conditions that are best for your plants. If your tent lacks proper ventilation, the plants you so much desire to grow might fail to produce as expected.

Also, if you overdo the fan you might end up damaging or harming your plants. So, how often to run an exhaust fan in a grow tent?

Exhaust Fan Running Time

The first step is to get your grow tent’s measurements. The dimensions will assist in the calculation of the exhaust fan running time. Use the measurements to calculate your tent volume.

Once you have the correct volume of your indoor grow tent, divide it by three.

The answer will give you a guide on the ideal running time of the exhaust fan inside the grow tent. Different grow tents sizes will require various duration for proper ventilation.

However, there is no precise time to indicate the run time. The main reason is that every stage of the crop requires specific attention. Let’s discuss this issue in full detail.

1. When Lights are ON

Lights produce heat and increase the interior temperature. In this regard, fans should circulate throughout this lighting period. As a rule of thumb, you should customize the pace of the fun appropriately to suit your needs.

2. When lights are OFF

When the lights go off, the heat production will automatically go down. You can wait for at least 20 minutes before you reduce the speed of the fans. Proper practice is to run them for at least 15 minutes hourly.

This will also depend on your geographical location. Some regions happen to be hotter even at night than others. Therefore, you need to consider such factors too. If your area is hot, then you may need to run the fan for longer periods.

3. Seedling Stage

For your seedlings to grow well, you should run the exhaust fans throughout the day. Their purpose is to maintain proper temperature and humidity. They should prevent the tent from getting too humid and keep also the gentle breeze around seedlings to ensure there is proper air circulation.

4. Flowering Stage

The flowering stage is the critical stage that will determine the growing success. The fans should run when the lights are on. During the dark period, let at least one fan to operate. During the late flowering stage, some flowers may produce a stinking odor. Therefore, run the fans throughout the entire period.

At Night

Colder nights may not need ventilation. During summer, you may schedule them to turn ON/OFF periodically. You can set the timer to go off at midnight. The action will balance the scenario.


Fans play a critical role in the plant’s growth. You only need to get some facts right to use them rightly. There is no specific run time as dictated by various factors. Some situations may require you to keep the fans running.

Fans can ventilate your tent to restore fresh air. On the other hand, they also control the humidity of the tent. Furthermore, the fans can control the internal temperatures in your grow tent by distributing them evenly.

As an indoor grower, you need to get proper yields that will increase your earnings and profits. Therefore, let your fans serve you appropriately as per your needs.

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