Benefits Of Growing Cannabis Indoors

3 Easy Ways to Fix Crop Heat Stress

Crop heat stress is a serious concern for cannabis growers. The plants thrive in warmer temperatures, but an excess of heat can cause yield loss and dry out the leaves. In this article, we will discuss 3 easy ways to fix crop heat stress so that your cannabis plants stay happy and healthy.

What is Crop Stress?

Crop stress is a condition where the grow room, greenhouse, or garden becomes too hot for the plants to thrive.

Every plant has an ideal temperature range. If the temperature gets over 75° Fahrenheit during the day inside your grow space, it is possible that this may be causing a crop heat stress problem.

How Does Heat Stress Affect Crops?

Cannabis likes it warm, but not too warm. An ideal growth space will be between 70 and 75 degrees Fahrenheit during the day and between 50 and 60 degrees at night. Too much heat can affect various aspects of cannabis growth such as:

  • Transpiration rates (the process by which a plant loses water through its leaves) increase with increases in temperature;
  • The rate of photosynthesis slows down as temperatures rise;
  • Yields may decrease due to increased leaf surface area exposed to light, resulting in less chlorophyll production on those leaves; this is known as “sunburn.”

Plants are also more susceptible to pests when they’re stressed out from extreme heat. The best way to avoid these problems is by providing plants with the ideal temperature range throughout the day.

How Can I Fix Heat Stress in Plants?

If your plants are suffering from a heat stress-related issue, don’t panic! There are several things you can do to help them get back on track:

  1. Loosen the soil around the base of affected plants; this will make it easier for roots to absorb water and prevent root rot.
  2. Provide plenty of water to help plants recover from heat stress and stay hydrated. You can also give them a gentle shower or misting with a spray bottle if they’re suffering from sunburn.
  3. If the problem is really severe, you might have to cut off any damaged leaves or stems as they won’t recover from a heat stress problem. Just be sure not to remove too much of the plant during your first attempt at fixing things, because this could damage it!

How Can I Prevent Heat Stress in My Cannabis Plants?

There are several ways to prevent heat stress when growing cannabis:

  • Provide an area of shade for your plants; this is especially important if you live in a hot, arid climate with little shade from trees or buildings.
  • Water your plants regularly to ensure that the soil stays moist. If you see wilting or leaf drop, it’s time for a big drink! Deepwater at least once per week and more frequently if temperatures are especially high. A drip irrigation system is best because this will deliver the most consistent and gentle watering. Avoid overhead sprinklers because they can damage leaves and stems.
  • Make use of reflective surfaces such as aluminum foil or white paint, which will bounce back the sun’s rays to reduce heat stress in your plants. Keep this in mind when designing your grow space. You might want to install a silver mylar on the north walls so that it reflects light away from where you grow your plants.
  • Providing a fan can also help to keep air circulating, which will prevent hot spots from forming in the grow space and keeps leaves cooler as they’re exposed to moving air. Make sure that you don’t point it directly at your plant because this could cause leaf burn. Placing it on one side of the room is usually sufficient.

Useful Tips

Try lowering your light levels so they are between 12-18 inches below your canopy when you are in full flower. This will decrease the light coming in from above which will cool down some of that ambient heat expended by lights and reduce HPS/MH output accordingly without causing any significant problems with growing cycle length.

Here are some other tips:


Turn off HID/HPS lights and fans during the day which will increase temperature, but turn them back on at sundown to bring things down. This will help your plants from dropping their leaves due to stress because of heat exposure during hot days or nights that you might normally have had your grow room set up for.

Lower your humidity levels by increasing ventilation or this will cause your plants to get stressed out too.

Placing fans outside of the grow room can help cool down air coming in from an open door if it’s still warmer than you’d like inside your space. You may need some type of exhaust system that is powered by a fan on timers that run intermittently for a few hours throughout the day and night.

You can also set up misters or foggers to your irrigation system during hot times of the year which will help cool down plants automatically as they suck up water from their reservoirs, even if there isn’t any air circulation present in your growing area. This is good because it’s easy and cheap to set up and test out.

If you have a small enough grow room, try sticking your plants outside during the day when it’s sunny for an hour or two (but not too hot) every few days which will help them get acclimated to outdoor conditions before bringing them back in at night if they are sensitive about new growing conditions.

Cooling systems

Cooling systems (such as air conditioning) can also be used in places where the temperature is too hot during certain times of year without running them 24/365 if you don’t want to do that, and use fans when it’s warm enough for your plants’ preference instead. Having a dehumidifier or two (or a basement or other area) for your grow room (or tent, closet, etc.) will also be good to help cool down the air and make sure humidity is kept at bay if it gets too high.

Be careful not to buy a dehumidifier that’s made for very low temperatures like the inside of freezers because some types can’t be used in higher temperatures, but most can.

Whatever you do to cool down your grow room during hot times of year will help prevent crop heat stress and the symptoms that go along with it so your plants can keep on growing strong!

If none of these things work for you or if they aren’t possible where you are at, then you can always try adjusting your grow times and buy a cooling system if you live in an area where it gets too hot for cannabis plants to thrive during certain parts of the year.


Tips for fixing crop heat stress: 1) check the temperature of your grow space; 2) create more airflow in your grow space; 3) add a fan to increase airflow and keep the air moving around the plants. To prevent heat stress in cannabis: 1) provide plenty of shade and reflective surfaces; 2) water regularly and deeply; 3) turn on fans to keep air moving around the plant. 4) Remove any dead leaves or stems from affected plants. If there’s a lot of damage, you may need to cut down the entire plant in order for it to regrow! This is not ideal because cannabis can be quite vulnerable at this point, so it’s best to try and prevent heat stress from the get-go.

Thank you for reading. Please share this post with a friend who may need the information, and comment below if you have any questions or concerns about your grow space temperature. See you next time!

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Christophe Rude

Christophe Rude

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