How to Cool a Grow Tent: 8 Best Cooling Solutions to Manage High Temperatures

Last Updated on April 21, 2022 by Gary Stephen

In this article, we would be particularly focusing on providing you with the best cooling solutions. This will help you know how to cool a grow tent, or room, and manage the high temperature inside. So let’s begin!

Temperature is one of the major and critical factors affecting the cultivar’s health in an indoor grow environment. Depending on its stage of development, the recommended range varies. Prolonged exposure to unregulated temperatures can turn out to be a disaster. Or worse, it might end up killing your plants. This is not an uncommon problem for growers though. In fact, anyone would at some point be dealing with such an issue.

What is the ideal temperature in the grow tent/room?

How to cool a grow tent

Before delving into the main topic, let us tap into the basics first.

So, what is primarily considered an ideal temperature for cultivars?

As mentioned, the suggested level of temperature differs. It’s based on the current growth phase of the plants. Generally, the optimal ranges are as follows:

Cloning Stage Vegetative Stage Flowering Stage Drying Stage Curing Stage
74°F to 78°F 70°F to 78°F 68°F to 75°F 65°F to 74°F 68°F to 72°F

You may use these figures above as a quick guide. This would help you set the most appropriate temperature for your grow space.

How does high temperature affect your plants?

You might be wondering how can hot temperatures cause damage. Here is what’s likely going to happen to your cultivars:

1. Disrupt the Photosynthesis.

Too much heat in the environment can cause the plant’s enzyme to lose its shape and ability to function. As a result, the rate of photosynthesis declines. Disruption in the process will leave your cultivars with less energy to grow and develop.

2. Decrease Seed Germination.

Up to a certain point, high temperatures can help speed up the rate of seed germination. Way too much heat can cause damage to the plants.

Fundamentally, seeds need fair amounts of moisture to germinate. Heat can instead induce evaporation of water leaving them less hydrated. Rather than getting absorbed by the seeds. The mere absence of moisture is what prompts the decrease in the pace of seed germination.

3. Disturb the Flowering Stage.

The flowering stage is very important in plant growth. This is where the formation of buds or flowers takes place. Exposing the cultivar in a room with too high temperature causes the buds to develop slower than usual.

Instead of the sought-after dense and sticky bud texture, the heat can make it become light, loose, and airy. It also becomes less potent and aromatic. Thus, compromising the quality of your produce.

4. Infestations.

High temperature goes hand in hand with relative humidity. When there is too much heat in the grow space, it also shoots up the chances of agitates the levels of humidity. There are actually a lot of consequences brought about by high RH including spider mites and the white powdery mildew.

Another type of infestation that may be possible to occur due to heat is root rotting. In this case, the high temperature causes deprivation of oxygen. This sets an environment for various pathogens like bacteria, fungi, or parasites called oomycetes. This can make your cultivar’s roots become unhealthy and appear as brown, slimy, and twisted.

What are the plant symptoms showing high-temperature in the grow room?

At some point, you might notice there has been an increase in the room temperature. Here are a few of the signs that you can take note of to assess if damage has already taken its course.

  • Stunted growth. or,
  • Grows tall and leggy.
  • Flowers become loose and fluffy.
  • Less aromatic.
  • The premature bearing of fruits.

If by any chance you notice any of the above is starting to occur, it’s best to take appropriate interventions immediately. Do this before the problem becomes even more extensive.

What are the best solutions to cool your grow tent and manage high temperature?

Now onto the very heart of the article.

Below are some of the best solutions you can do to handle heat issues within your grow space.

Read Also: How to Manage Light Interruptions During the Flowering Cycle

Solution #1: Improve your air circulation and ventilation systems to cool a grow tent

Because hot air can accumulate in a room, you have to boost the exchange of air within. By that, it means you have to speed up the release of warm air out while increasing the intake of cool air as well.

Here are some of our inline duct fan recommendations:

TerraBloom 4 Inch 160 CFM Inline Fan with Variable Speed Controller

AC Infinity Cloudline S4 Quiet 4 Inch Inline Duct Fan with Speed Control

Vivosun 6 Inch Inline Duct Booster Fan 240 CFM

TerraBloom 6 Inch Inline Fan 395 CFM

Tophort 8 Inch Inline Duct Fan 800 CFM

It is necessary to install fans that are powerful enough to cover the entire area. This will help you achieve efficient air movement in the room. Also, it would be great to invest in a good temperature and humidity controller to aid in the monitoring. As well as automatic regulation when it detects that the levels are getting beyond the desired range.

Here are a few of our top picks for temperature sensor controllers:

Titan Controls Spartan Series Complete Digital Environmental Controller

Vivosun Digital Heat Mat Thermostat Temperature Controller

AutoPilot APE4100 Eclipse F60D Digital Environmental Controller

Inkbird Temperature and Humidity Controller

Titan Controls HGC702851 Classic Series Saturn 5 Digital Environmental Controller

Solution #2: Promote uniform air circulation throughout the grow room.

The grow space would be able to maintain appropriate even temperatures throughout the room. That means when you set a specific temperature it should be the same across the entire room. There will be areas where a slight difference is likely expected, for example, the spaces near the lighting system. Then, it is best to provide oscillating fans to encourage the dissipation of heat.

Here are a few of our top picks for oscillating fans:

Vivosun Patented 6 Inch Clip-On Oscillating Fan

Secret Jardin Monkey Fan 16 Watts 6 Inch

Hurricane HGC736520 Classic Series Clip Fan 6 inch White

Bovado USA 6 Inch 2-Speed Adjustable Tilt Clip-On Fan

Hydrofarm HORF8 Active Air 7.5 Watt Ultra Quiet Brushless 8 Inch Clip-On Fan

Solution #3: Encourage humidity to cool your grow tent.

As we know by now, the issue of temperature is always associated with humidity and vice versa. We cannot avoid discussing one without the other because both are interrelated.

To further explain its relationship, you have to understand that the warmer the air, the more moisture it can hold. When the temperature is high, the more water will get drawn up in the air, and the relative humidity becomes low. When the air temperature cools down, the relative humidity now rises in effect.

So, considering the principles stated above, we’ll try to counterbalance the high temperature of the grow room. This means increasing the level of relative humidity within the space. By increasing the RH, plants will now be able to absorb more moisture and cool down.

To ease the increase of humidity, it is best to invest in a good quality humidifier. Here are some of our best picks:

Vivosun 6L Ultrasonic Humidifiers

Ideal-Air 700860 Commercial-Grade Humidifier GSH75

Horticat U80Pro Ultrasonic Mist

Air Bear Trion Duct Mounted Atomizing 24V Humidifier Mister Mini

Vornado Evap40 4 Gallon Evaporative Humidifier

Solution #4:  Reduce the concentration of the nutrient solution.

When the plant is exposed in an area with high temperatures, the leaves tend to increase its transpiration in an attempt to cool down itself. Besides, this natural defense mechanism also has a perilous after effect.

As a consequence of that high transpiration, the root will in return compensate for the moisture loss by absorbing in more water. Unfortunately, the roots are not only consuming plain fluids. But, also drawing in the nutrients from the soil. Hence, resulting in toxicity of the cultivars.

Common signs of over-fertilization include stunted growth, dried out, or burned leaf margins. Also, wilting and even death if not rescued immediately. To prevent such from happening, it’s better to lessen the concentration of the nutrient solution you are using. You can do this by diluting it with pure water.

Here some of the nutrient solutions we highly suggest:

Prescription Blend Plant Nutrients Optimized in Medicinal Gardens

Mega Crop 1000 Grams Complete Hydroponic and Soil Nutrient

Cutting Edge Solutions CES2604 Uncle John Blend 2.5 Gallon

Advanced Nutrients Bloom, Micro & Grow Pack of 3 1 Liter

Good Stuff Grow 4 Pack Complete Set

Solution #5: Chill the nutrients is also a way to cool your grow tent/room.

Another quick fix to relieve the plants from heat is to chill the nutrients before spraying. It is a great tip to try and at the same time, still, enforce routines to increase your yield. Chilling the solution at a temperature of 55°F to 65°F can help the cultivars to immediately cool down.

To maintain the nutrients cooled with consistency, we recommend using hydroponic chillers. Here are our best picks:

Active Aqua AACH25HP Hydroponic Water Chiller Cooling System

EcoPlus Chiller 0.25HP

Hamilton Technology Aqua Euro Max Aquarium Chiller

JBJ Aquarium Arctica Titanium Chiller

Hydrofarm Active Aqua Chiller 1/10HP

Solution #6: Minimize the usage of lights.

Raising the height of the light source to decrease the temperature is one common misconception among some growers. Actually, it can lessen the direct heat to the plants but not the entire room temperature. Thus, this isn’t a solid solution.

One of the most basic things you can actually do is to reduce the usage of lights. You can either switch off a few bulbs or dimming it halfway for a certain period of time. Don’t worry, it is okay to reduce your lights for a short while. Remember, you are doing this to address an existing heat problem.

Here are a few of our  recommendations for dimming ballast:

Yescom 250W Digital Electronic Dimmable Ballast Grow Light

Vivosun 400W Dimmable Electronic Digital Ballast

Hydrofarm Quantum QT600 Dimmable 600W Digital Ballast

Tophort 1000 Watt Digital Dimmable Electronic Ballast

iPower GLBLST1000D Horticulture 1000W Digital Dimmable Electronic Ballast

Solution #7: Use air-cooled reflector hoods.

Apparently, lights are the major contributors to heat inside the grow room. So, you can opt to add an air-cooled reflector hood. This is to help mitigate the warm temperature emitted from the light sources. This device, it’s said to cut off at least half of the generated heat.

Here are our best picks for reflector hoods:

iPower 6 Inch Air Cooled Reflector Hood

Giantex 6 Inch Air Cooled Hood Reflector

Hongville 6 Inch Grow Light Air Cooled Hood Reflector

Grow1 Lil Hood 6 Inch Hinged Mini Air Cooled Grow Light Reflector

Hydro Crunch ND940000500 8 Inch Extra Large Air Cooled Grow Light Reflector

Solution #8: Schedule the running of lights at night time.

However, if you do not feel comfortable minimizing your lights at all, then it would be a better option to instead shift to an evening schedule. Rather than running all the lights in the morning. Ambient temperature is lower during the nighttime. Thus, it would not further contribute to heat accumulation in the grow room.

To help you manage the timing, we can suggest using an electric timer. Here are some of the best:

iPower 24 Hour Plug-In Mechanical Electric Outlet Timer

Canagrow 7 Day Heavy Duty Indoor Plug-In Timer

iPower 7 Day Heavy Duty Digital Programmable Electric Timer

Nearpow Dual Digital Light Timer

Purple Reign 115 Volt 15 Amp Digital 7 Day Dual Outlet Grow Light Timer

Final Thoughts of How to Cool Your Grow Tent or Grow Room

There it goes our best cooling solutions to help you manage high temperature and cool your the grow tent/room. They are easy to follow and, they are already proven to deliver positive results.

Try to do at least one, or even combinations of the said measures and see which one works for you the best. Some of our suggested products may need you to shell out a bit of your budget. But, you can assure that these devices will give you a good return of your investment in the long run.

Gary Stephen
Gary Stephen

Hi, I am Gary Stephen. I have been gardening for a long time. Gardening gives us much benefits and pleasure. Many of us desire to have a garden, but it cannot fulfill the desire for the proper guide or instruction of gardening. So, I am eager to help them. For this purpose, I have developed the website to make a garden with the proper guide. So, you will get me beside you if you want to know anything about gardening.