3 Proven Supplements to Help Cannabis with Heat Stress


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Sep 19, 2009
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Mariposa County CA
I ran across this article and thought I would share since Summer is here. ~ Burnin1

From Grow Weed Easy

3 Proven Supplements to Help Cannabis with Heat Stress
Updated Jun 10, 2019
by Nebula Haze

High temperatures can make growing cannabis a lot harder, even if you’re growing with heat-resistant strains. Droopiness, nutrient deficiencies, and overall slow growth are common symptoms of heat stress, whether your plants are growing indoors or outdoors!

We already have tutorials on controlling heat indoors, circulation and exhaust, as well as how to help outdoor plants during a heatwave, but are there any marijuana supplements that boost the plant’s ability to survive the heat without changing anything else about the environment?

Actually…yes! There are 3 specific supplements that are known to help cannabis plants be more overall resistant to heat stress, drought, and high temperatures!

Help your marijuana plants be more resistant to heat stress, unlike this poor baby!

1.) Seaweed Kelp Extract
There are numerous studies showing that seaweed kelp extract is beneficial for heat-stressed plants when used as a supplement. Seaweed kelp extract (available as a liquid or powder) has been shown to increase yields, growth rates, and heat resistance in plants experiencing environmental stress.

Kelp naturally contains lots of trace elements and minerals that have protective properties for plants. Studies have shown that supplementing with kelp can increase plant yields, growth rates, and heat/drought resistance for many species of plants.

Besides protecting against heat, kelp supplements may also enhance seed germination, increase uptake of plant nutrients, and give more overall resistance to frost and fungal diseases.

2.) Humic Acid Supplements
Humic acids are naturally found in the soil, but adding extra can be beneficial. Plant supplements for humic acid are usually derived from leonardite, a substance that is mined near the surface of lignite deposits (lignite is sedimentary rock that formed over millions of years from compressed peat). It is a waxy, brown substance.

Humic acids have protective abilities and can help cannabis plants deal with water stress and drought. Additionally, there is quite a bit of evidence (mostly with many different types of grass, but also with plants like soybeans and corn), that combining humic acid supplements with seaweed kelp extract actually increases the overall effectiveness of both supplements. They may have a synergistic relationship!

Not only do humic acid supplements help protect the plant against water stress, but they may also enhance the heat-resistance benefits of using sea kelp extract!

3.) Silica Supplements
Silica is not a “required” nutrient and your plant won’t suffer from Silica deficiencies. However, supplementing with extra silica offers additional support to plant cell walls. This helps your plants be more resistant to heat and other types of stress. This not only makes cannabis plants more resistant to heat, but it also helps prevent stems from bending or breaking when buds get big and heavy! Have you ever had your buds fall over from being too heavy? Silica can help!

Botanicare Silica Blast or General Hydroponics ArmorSi are examples of silica supplements made for plants

Whenever possible, try to get a silica supplement from the same manufacturer that makes your base nutrients to help ensure everything works well together.

auto-flowering strains to be relatively sensitive to heat since they originated in Siberia, but some strains have been mixed with heat-resistant strains to make them more suitable for warmer climates.
  • Many Indica plants, which also come from cool climates, can be surprisingly sensitive to the heat.
[paste:font size="5"]Kaya Gold
  • In addition to doing well in the heat, this strain is overall easy-to-grow and resistant to pests and mold
  • Has a surprisingly short flowering stage (8-9 weeks) for a Sativa-dominant strain, and doesn’t get too tall
  • Buds produce very heavy effects – more of a ‘brain-melter’ with couchlock than a good choice for social situations
  • Does well indoors, and grows exceptionally well outdoors (plus it is ready to harvest earlier than most other strains)
  • Great yields
  • Get Kaya Gold from Seedsman (ships to US)
The Kaya Gold strain thrives in the heat. This plant experienced many days over 100°F (38°C) yet plants were unfazed!

Northern Light by Royal Queen Seeds
  • There are many versions of Northern Light, and all tend to be hardy strains
  • However, the version by RQS is particularly resistant to many problems, including heat
  • Get Northern Light from Seedsman (ships to US)

THC Bomb Auto
  • An auto-flowering plant that’s ready to harvest about 75 days from germination in my experience
  • I’ve grown it several times, and it always turns out well (though they all grow a little different)
  • This strain experienced temperatures up to 89 F during the middle of summer, and never skipped a beat
  • Very potent strain, and good yields
  • Try out THC Bomb Auto
Examples of THC Bomb Auto at harvest

Learn More About Heat and Light Stress

5 Ways to Help Indoor Cannabis Plants Deal with Heat

How to Help Outdoor Marijuana Plants During a Heatwave

Using Coco Coir as a Growing Medium <– One of the most heat-resistant growing mediums!



New Member
Oct 21, 2016
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Thank you burnin1. I do have dry versions of all of these things. Still just learning to help my plants without hurting them.


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Nov 7, 2008
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Glad i was able to point you to his thread.👍
Jul 22, 2022
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I started to grow my own two bushes around four months ago, at the end of February. By the time summer came, at the beginning of June, I had noticed that my leaves were dried and of a yellow color. I've read everything about how to groom, how much water it needs, when it needs water, etc. However, I didn't consider that the temperature outside would affect my plants. I used some humic supplements on one bush and on another because I've heard that anabolics also help with plants.
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