What To Do When Your Marijuana Grow Room Gets Too Hot Or Humid?

October 25, 2019

What to do when your marijuana grow room is very humid? The grow space will naturally be humid because the marijuana plants emanate moisture that collects in the garden space. To get rid of that moisture, the easiest thing you can do is ventilate the room and replace the moisture with drier air.

For gardens that are closed systems, a dehumidifier must be used. Dehumidifiers have cold tubing that will condense the moisture in the air and make it less humid. Of course, they do release heat and can make the grow space too hot if you’re not careful. To avoid overheating, just affix some air vent tubing to the dehumidifier’s exhaust so that the heat is pointed outside the grow space.

If the room is both hot and humid, an air conditioner could work toward removing the moisture while cooling the garden. Make sure to download my free marijuana grow bible at this link and learn how to create perfect conditions in your marijuana grow room.

Hot grow room

What to do when your marijuana room is too hot? There are plenty of ways to cool down an overheated grow room. See what suits you best:

-It can be ventilated to remove the heat.

-An air conditioner can replace the hot air with cool air.

-Prior to flowering, an air cooler that evaporates water to lower the temperature can be beneficial. These coolers won’t add too much moisture to the air and are ideal and extremely efficient during vegetative growth. They are, however, not good for plants in the flowering stage because they create too much moisture.

-If the temperature drops drastically at night, you could solve the heat issues by running the garden’s lights at night instead of the day.

-Hydroponically-grown plants can shift temperatures based on how hot or cold the water is. You can keep the plants cool even if it’s technically hot outside. If the room temperature is somewhere in the 80’s (27-30*C), try to keep the water temperature in the 60’s (15-20*C). Growers can install aquarium water coolers to keep the water cool automatically.

-Any heat producing equipment should be taken out of the grow room is at all possible (e.g. light ballasts and large pumps).

-Avoiding heat starts from the beginning. Take preventative measures to ensure that heat will not be an issue with your crop. Air- or water-cooled lights keep the lamp’s heat from entering the garden. A series of tubes takes the heat from the lamps to the outside without affecting the temperature in the grow room itself.

Download my free grow guide and order some high quality seeds at this link here. We ship seeds to the US, CA and many other countries. For any growing related question please visit the marijuana support page.


The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]


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  1. By Problems That Cause Marijuana Plants To Stress ,15 Jul 2015
    […] When it comes to temperature, cannabis plants like it hot, but there is a point at which it can become too hot. Anything over 80 degrees Fahrenheit is likely to be less than beneficial for most varieties. If your […]Read More
    1. By Reuben ,11 May 2020
      Bottom leaves are stating to turn purple is a dry out white widow 3 weeks old what causes this and how do I fix it?
      1. By Kim ,26 May 2020
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  2. By Symptom Checker – Identify Marijuana Plant Problems ,20 Jul 2015
    […] Humidity and temperature […]
    1. By Kim ,26 May 2020
      The picture above on the right where the text says "curling leaves". It doesnt mention anywhere what that is a symptom of. I'm in the need of advice regarding that one, help is appreciated. Thanks!
  3. By G A ,30 Aug 2015
    I received some of Mr. Bergman's 'GOLD' seeds, germinated them, all sprouted and are growing. At 22 days since poking their little heads above ground they are about 8 inches tall with 8 sets of leaves. I think I should […]Read More
  4. By latewood ,02 Sep 2015
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  5. By Kevin ,27 Nov 2015
    First week's of flowering, what nutrients do I need to get potent big buds. I have earth juice bloom but what do I need to use from week one throughout flowering
  6. By latewood.ILGM ,27 Nov 2015
    You have a bloom nutrient. That alone will do the job. You could research additives to the EJ Bloom. I would see what Earth juice offers, 1st.
  7. By Iripplipps ,14 Apr 2016
    My plants are 3 weeks old and are doing well. I'm now starting to increase nutrients accordingly. When is it time to remove large fan leaves?
  8. By latewood.ILGM ,16 Apr 2016
    Iripplipps, You never want to remove big fan leaves. They are the heart and soul of the plant. If the plant has issues; it is the Fan leaves that provide the balance to keep the plant healthy. Fan leaves will […]Read More
  9. By Steph ,30 Sep 2016
    What's the optimum temp & humidity for indoor plants?
  10. By latewood.ILGM ,03 Oct 2016
    Optimum temps are 70-80f and humidity 50-60% in veg, and 40% in bloom. I suggest you download and read our free Grow Bible, then join our support forum Happy growing :)
    1. By mark genanatti ,09 Apr 2017
      so in veg no hotter than 60 degrees
    2. By Nasa ,16 Dec 2020
      My grow tent humidity around 70-80%... How to increase
  11. By Can Stress Cause Hermaphrodite Marijuana Plants? ,28 Oct 2016
    […] temperatures being too high, or other environmental issues that the plant doesn’t thrive in […]
  12. By Robert Toth ,18 Jul 2017
    I am a first time hydroponics grower, I thank you for the Grow bible. My infant plants look vary good, nice leaf production & root production. I use the H2O to grow 5Gal bubbler Bucket w/ Advanced Nutrients 2 part […]Read More
    1. By latewood.ILGM ,21 Jul 2017
      Robert, After using An, then GH, then Dutchmaster, and Foxfarm, I did a grow with Roberts ilovegrowingmarijuana Flower power starter pack. This is the easiest nutrients I have used considering you do not need to add anything else and can […]Read More
  13. By Michael ,07 Jul 2019
    Hello ILGM peeps! to be here! Can't wait to start my first grow!
  14. By Casey ,21 Nov 2019
    Hi all, I have a particularly difficult climate where i am. i have a grow room with 3 white widow plants, after almost 3 months I have changed from hd to cfl and 12/12, as my room easily gets to […]Read More
    1. By Casey ,21 Nov 2019
      Hi all, I have a particularly difficult climate where i am. i have a grow room with 3 white widow plants, after almost 3 months I have changed from hd to cfl and 12/12, as my room easily gets to […]Read More
      1. By Latewppd_ILGM ,01 Dec 2019
        Join us here: support.ilovegrowingmarijuana.com so we can go back and forth with you in order to attempt to help you out. We cannot do an aggressive Q & A here in the blog. I do not see how with an […]Read More
  15. By Shirley ,13 Jun 2020
    I love growing & smoking weed
  16. By David ,12 Jul 2020
    My harlequin strain is curling very strangely the Bergman gold is fine. Plants are 10inches high. Nice color.
  17. By Wal ,29 Jul 2020
    Just had a look at your site quickly, appreciate everything you do. Will get back to it soon. Thanks bro. Well done. Wal. From down Under.

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