How to Keep a Grow Tent Cool: 6 Easy Cooling Solutions

The main problem grow tent planters struggle with is heat. A 4×4 grow tent isn’t that big. And if the plant density inside the grow tent is high, tackling the heat is a real challenge. So, how to keep a grow tent cool?

You can take several steps to minimize heat inside the grow tent. Moving the grow tent to a cooler place can be a good solution. You can also use LED grow lights to lower the heat. Running oscillating fans inside the tent will help blow out the excess heat. Using an air conditioner will also greatly help.

I will explain these ways in detail from my experience as a grow tent planter.

Why Keeping a 4×4 Grow Tent Cool Important?

When plants are in the open air, the generated heat can easily be spread away to keep the surrounding temperature ideal for the plants. But this gets very difficult when you use grow tents. As the space is confined, the generated heat can’t easily escape the grow tent. So, the temperature rises inside the grow tent and affects the growth of your plants.

Excess temperature doesn’t only affect the growth of the plants but also damages leaves and other parts of the plant. Higher temperature causes plants to sweat more than usual. This way, plants evaporate more water than usual, which can make these plants vulnerable. So, you must keep a 4X4 grow tent cool to ensure optimal plant conditions.

How to Keep a Grow Tent Cool?

Most of the methods I mention here will require no additional cost. Apply these techniques to ensure better-growing conditions for your plants inside the grow tent.

1. Move the Grow Tent to a Cooler Place

If the grow tent is located where sunlight directly falls upon it, the temperature inside the tent will always be higher than usual. The temperature in basements is usually lower than in the house. So, you can move the grow tent to the basement.

In that case, you must plan a good ducting route so that the hot air inside the tent can be blown out through the duct. This will help you keep the temperature down in a 4×4 grow tent.

2. Use Oscillating Fans

Oscillating Table Fan

You might already have these fans in your house. Place an oscillating fan inside the grow tent and direct it towards the blow duct so that it can blow hot air from inside the tent.

Using such a fan will remove heat to keep the tent cooler. Remember, the fan should not be directed toward the room where you keep the tent. This way, the fan will blow out the hot air from the tent into the room. And the tent will again suck that hot air leaving the fan useless.

3. Use LED Grow Lights


HPS grow lights are very common in 4×4 grow tents. Many people also use CMH lights. But these lights generate a lot of heat that will increase the temperature inside the grow tent to a great extent.

To handle this situation, you need to use LED grow lights. These lights are usually smaller than HPS or CMH lights and will generate less heat. As a result, the grow tent will be cooler than before.

Buying LED grow lights won’t cost much. You should definitely spend the amount to ensure the perfect condition for the balanced growth of your plants.

4. Use an Air Conditioner


If the season is too hot and no other ways work enough to keep the grow tent cool, you can use an air conditioner to decrease temperature in 4×4 grow tent. Placing a split air conditioner inside the grow tent will keep it cool even when the outside air is hot.

When the climate is moderate, having an air conditioner in the room the grow tent is located might be enough. Air conditioners can also help keep the humidity lower in the grow tent.

Related: How cool grow a tent without ac

5. Place Any Electronic Equipment Outside the Tent

From the LED light ballasts to hydroponic equipment, nothing should be inside the grow tent. This equipment generates some heat while running, and the accumulated heat can increase the temperature inside the grow tent.

So, you need to move this equipment outside. You can use extension cords if necessary.

6. Place Ice Boxes Inside the Tent

This can be a cost-effective solution to keep your grow tents cool. You can use regular ice or dry ice to lower the temperature inside the tent. Pointing the oscillating fan towards the ice box will help spread the cooler air.

Using regular ice will also work if you can’t manage dry ice. But in this case, you can add salt to the water and freeze it. This salt ice will remain solid for longer than regular ice.


What temperature is too hot for a 4×4 grow tent?

Depending on the stages of a plant’s life cycle, the tolerable temperature can vary. If you consider the early flowering stage, 80℉ should be the maximum temperature inside the grow tent. Anything higher than that might be too hot for a grow tent.

What happens when your grow tent is too hot?

If the temperature inside the grow tent is too high, it will reduce the growth of your plants. Also, the plants can get wilted easily.

Can plants recover from heat stress when I cool down the grow tent?

When the temperature rise isn’t severe and doesn’t sustain for long, plants might recover from the heat stress. But if this happens too frequently and for extended periods, plants might not recover.


I tried to show you the most effective and economical methods of how to keep a grow tent cool. Adding a fan or an air conditioner is the best way to remove heat from the tent. But methods like moving the tent or rerouting the ducts will also work when the tent is small.

Use these methods to maintain the ideal growing condition for your plants inside a grow tent.

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