Cannabis Heat Stress

Cannabis Heat Stress: Prevention and Treatment

When you grow your pot plants, you must understand the reason why cannabis plants experience heat stress. Do you know why this is happening to your cannabis plants? Keep reading to learn more about cannabis heat stress and how you can get your marijuana plants to survive.

What Is Cannabis Heat Stress?

Cannabis heat stress refers to a condition wherein marijuana plants exhibit signs of stress, such as yellow or brown spotting because of being exposed to places where there are so much light and heat. It can occur in the grow room where artificial lighting is used.

When you think about heat stress for your plants, you are probably wondering what will happen when they get too much heat. The answer is very simple; they will die. You do not want to harvest and replant them because this will cause problems in your garden. These plants will not grow as quickly and they will not be as productive when they are subjected to too much heat. If you are growing your marijuana and you are growing marijuana indoors, you may not even have to worry about this because it is a rare case.

Causes of Cannabis Heat Stress

Heat stress can be caused by too many light hours. That is why you are going to have to determine how much heat is needed to keep the roots alive and healthy.

It can also be caused by too little heat or too much heat. The reason it is so important is that the heat from the sun causes the roots to expand. As these roots expand, the plant experiences water loss and this leads to plant decomposition. This is where you will see the leaves and stems turning brown.

Signs Of Cannabis Heat Stress

One way to know if your plant needs heat is to check the foliage or the buds. When the plants grow thick, they are growing heat. If the leaves and buds begin to turn brown, it is a sign that the heat is getting to the roots.

Step-by-step Guide: Prevention and Treatment For Cannabis Heat Stress

Treatment: Restrict Light Exposure

Cannabis plants need at least eight hours of daylight each day. However, when the sun goes down, you should put a couple of fans on the plants to remove some of the excess heat from the area. You should also consider the temperature of the soil as well.

The heat will eventually destroy any plant life it can touch. This is why you do not want to have your plants close to an open window or a hot oven all day long, as these factors will help speed up the process. This is something that should be avoided at all costs because if this happens, your plant will be ruined.

Once the heat has started, there are a few things that you can do to stop it. 

Here’s how:

  • You can turn the lights down.
  • Remove any plants that are growing too tall.
  • Turn off the fans and shut all vents to lower the temperature. 
  • You can also place plastic sheets between the plants to reduce heat transfer and make sure that no moisture is escaping.

Prevent Cannabis Heat Stress

Check the following steps and tips when managing cannabis heat stress:

1. Water Your Cannabis Plants Properly

To prevent extreme heat from damaging your plants, make sure that you water them properly. Here’s how:

  • Use a high-quality organic potting soil that has lots of moisture and make sure that you give them good drainage.
  • There should be plenty of water throughout the day to keep the roots moist and to prevent mold from forming. 
  • If your plant is getting too much water, this can encourage root rot, which can cause damage to your plants.

2. Repot Cannabis Plants

One reason that your cannabis plants experience heat stress is that they have been overgrown by the mother plants, so try to prune and repot them as soon as possible after they have been established. This will give the mother plants time to properly grow out the rest of the mother plant.

Here’s how to repot cannabis plants:

  • Choose the cannabis plants that need repotting.
  • Wet the soil to make repotting easier.
  • Dig a hole.
  • Loosen the soil.
  • Flip the starter pot and tip. Don’t shake the cannabis plant because it will damage the root system.
  • Transfer the marijuana plant to the new pot after treating the soil.

3. Maintain Good Ventilation

Grow rooms should be maintained with a closed-up space or one that has air circulating all the time and is heated, but should not be heated so high that water vapor is not able to escape. This can lead to the rotting of your potting soil and even lead to mold that could eventually kill your plants.

4. Choose The Best Growing Medium

One of the best ways to stop heat stress from being so much of a problem in your grow room is by choosing the best growing medium for your plant. Some mediums such as vermiculite and coir will help prevent moisture from getting into the potting mix, while others such as sand or perlite will make it easier for your plant to retain moisture. This can also keep the temperatures under control and will keep the humidity under control.

5. Consider Proper Artificial Lighting

Light is another factor to consider. There are different types of lights, and you need to know which ones are best for the plants. The main light you need is a standard 12-volt, but some lights also come in the form of fluorescent tubes.

During the day, the plants must receive sufficient light and enough water. At night, you need to use lights that require less light so the plants will not burn out. Avoid using high-powered LEDs because this light emits more heat than CFL and fluorescent lights. 


Cannabis heat stress is a serious issue caused by too much heat and light exposure. Thus, the treatment is reducing excess light, along with proper watering and fertilizing of your cannabis plants. Aim to avoid burnout by adjusting the placement of the pots in your grow room or adjusting the artificial light. Maintain good ventilation, moisture, and temperature to avoid cannabis heat stress and other related diseases.

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