Skip to Content

How to Keep Your Grow Tent Warm – 9 Methods

Grow tents are great for growing plants. They make it easy to have a fully contained environment that you can control, from the temperature to humidity levels. Keeping your grow tent warm is vital if you want your plants to thrive.

Here are 9 methods to keep your grow tent warm:

  1. Insulate your grow tent.
  2. Reduce your grow tent’s fan speed.
  3. Use room heaters to heat your tent.
  4. Add more grow lights to your tent.
  5. Monitor the temperature inside the tent.
  6. Use a heat mat to raise your grow tent’s temperature.
  7. Add double-glazed windows to your tent.
  8. Use an air diffuser inside the tent.
  9. Close your grow tent doors.

Warmth is essential for your plant’s growth, and there are many ways to ensure that you keep your plants happy and thriving. In this article, we’ll detail these methods and how you can use them to keep your grow tent warm.

As an Amazon Associate, I earn from qualifying purchases.

This is my grow tent setup. and this season I’m growing lots of peppers! Photo by Spicy Trio

1. Insulate the Outside of Your Grow Tent

The first step to keeping your grow tent warm is insulating your walls, floor, and door. This process will ensure you don’t lose warmth to the outside or let in the chilly air. Always make sure to insulate the outside of your grow tent and not the inside.

Always insulate the outside of a grow tent, it’s less of a fire hazard than when placed inside. Additionally, you don’t want to cover the reflective material that lines the inside of your grow tent, which will reduce its effectiveness.

There are several options for grow tent insulation, but the following two options work best.

  • Reflective Mylar
  • Bubble wrap. This material is not as effective as Reflective Mylar but is much cheaper. Tape the bubble wrap to the inside of your grow tent.

You can use other materials that you may have on hand for insulation, such as;

  • Fiberglass foam board
  • Thin sheets of wood
  • Corkboard
  • Cardboard

The important thing is to cover as much surface area with an insulating material as possible. The more you have covered the walls, floor, and doors, the better insulated your grow tent will be from outside temperatures.

Insulation materials are cheap and easy to install; most can be cut with a pair of scissors or a box cutter if needed. They’re also straightforward when removing them at the end of the growing season or if they need replacing because they’ve begun falling apart after repeated use over several years.

2. Reduce Your Grow Tent’s Fan Speed

A fan is essential for your grow tent, as it circulates air and keeps the temperature inside from getting too warm. However, if your grow tent is cold, you can lower the fan’s speed to reduce the amount of cold air circulating.

If your fan has several speeds, you can set it to a slower speed, so it runs more slowly. But if you don’t have that option, you can unplug the fan for a few hours to give your grow tent a chance to warm up. This will allow less cold air to enter the tent and will help raise the overall temperature.

Alternatively, you can try putting something in front of the fan to reduce the airflow. You can use a piece of cardboard, a blanket, or even a cloth. Make sure that whatever you use is breathable so that the moisture from your plants doesn’t build up as condensation.

If you’re looking for a variable speed fan for your grow tent, I recommend Growbuds 6 Inch Oscillating Clip-On Fan which can be purchased at The clip-on feature of these fans is perfect for grow tents.

3. Use Room Heaters to Heat the Room your Grow Tent is in

One of the best ways to keep your grow tent warm is to use room heaters inside the room your grow tent is in.

Warning: never put room heaters inside a grow tent as it is a serious fire hazard. Make sure the heater you purchase is right for your room, for example in a small room inside your home an electric propane heater would not be a good choice.

There are a few different types of room heaters that you can use:

  • Electric heater: These are the most common type of room heaters. They’re easy to use and relatively cheap to buy. However, they can be a fire hazard, so read the instructions carefully before using one.
  • Propane heater: These are a great option if you want a portable heater to move around. Propane heaters are also more efficient than electric heaters, saving you money in the long run. However, they can be dangerous if misused, so follow the instructions carefully, and in many cases, these will be too industrial for your needs.
  • Oil-filled radiator: These heaters are filled with oil and have a built-in fan that circulates the heat. They’re safe to use and are very effective at heating a room. However, they can be expensive to buy.
  • Ceramic heater: These heaters use ceramic plates to generate heat. They’re safe to use and are very effective at heating a room.
Photo of grow lights hanging above pepper plants in a grow tent
I used two decent-sized LED panels inside my grow tent. Photo by Spicy Trio.

4. Add More Grow Lights to Your Tent

If your grow tent isn’t warm enough, you can add more grow lights to help heat things up. Grow lights create an environment that is more conducive to plant growth and will help them thrive. You can also use the lights to supplement your heating if you find that your grow tent is still a bit chilly.

There are two types of grow lights that you can use:

  • Fluorescent lights are the most common type of grow light and are very affordable. They’re also very effective at providing light for your plants.
  • LED lights: These lights are more expensive than fluorescent lights but also more powerful and last longer. They’re also more efficient, saving you money in the long run.

Make sure to research the best grow lights for your specific setup, as different plants require different types of light.

My favorite grow led, which I use personally, is the VIPARSPECTRA P1500 LED Grow Light found at I have been using this one nonstop, and the ability to adjust the light output makes it my favorite.

Photo of a heatwave showing a sun against a orange sky with a thermometer showing temperatures above 100 degrees F
Photo by Günter Albers

5. Monitor the Temperature Inside the Tent

Temperature is one of the most important factors to monitor when growing plants indoors. A sudden temperature change can stunt or even kill your plants.

The best way to keep an eye on the temperature inside your grow tent is to use a thermometer. Thermometers allow you to track the temperature and make adjustments as needed.

If the temperature inside your tent is too low, you can use a space heater to warm it up. If the temperature is too high, you can use a fan to cool it down.

6. Use a Heat Mat to Raise Your Grow Tent’s Temperature

Keeping the soil warm is crucial if you’re growing in a tent. A heat mat placed underneath your pots can help regulate the soil temperature and provide a consistent, warm environment for your plants. The warmth helps prevent your plant from freezing, which may lead to root rot and other health issues.

A heat mat will also help keep the temperature even throughout the grow room, preventing cold spots that can damage your plants. Your plants will grow faster and more efficiently with a heat mat.

Make sure to get a heat mat that’s the right size for your grow tent to maximize the amount of heated surface area available to your plants.

I use the VIVOSUN Seedling Heat Mat for my grow tent.

7. Add Double-Pane Windows to the Room Your Grow Tent is in

Double-Pane windows are a great way to reduce heat loss in the room you keep your grow tent. The double-pane window helps maintain a more consistent temperature in the room.

Double-paned windows are more efficient than single-paned ones because they keep the heat in the room better. Heat in a room is mostly lost through the window area of rooms, and the double-pane window helps prevent this from occurring.

8. Use a Small Humidifier Inside the Grow Tent

You can use a small humidifier inside a grow tent to increase the temperature. The increase in humidity will help keep your grow tent warm.

I have an entire article covering how to raise the humidity in a grow tent if you’re curious to find out more.

Make sure it is a small humidifier, as a large one could add too much humidity to your grow tent, which can negatively impact your plants.

If you’re looking for a small grow tent humidifier, I recommend the VIVOSUN Air Humidifier 4L Cool Mist Humidifier. Vivosun is a reputable brand and makes many great grow tent products.

9. Close Your Grow Tent Doors

One of the simplest ways to keep your grow tent warm is to close its doors. Closed doors help keep the heat inside and prevent it from escaping.

If you have a fan or an exhaust system installed in your grow tent, ensure you don’t point it towards the doors, or it will push the warm air out. This process will create a draft and reduce your tent’s indoor temperature.

Key Takeaways

You don’t have to break the bank to keep your grow tent warm. There are a few simple and inexpensive ways to do it, such as:

  • Insulating your walls, floor, and doors
  • Closing the doors
  • Reducing fan speed
  • Using a humidifier
  • Adding double-paned windows to the room
  • Use a heating device in the room

If you follow these tips, you’ll be able to keep your grow tent warm.