Mold & Fungus

If you already have experience with growing, there is a great chance that you had to deal with some type of mold/fungus attacking your plant. This is pretty common and especially outdoor, it’s sometimes hard to prevent from happening. If you want to prevent or treat a fungus infected plant, you have to look at the environment/climate your plants are living in because thats the thing all types of fungus/mold have in common!

Fungus/mold in general likes:

  • A high humidity
  • no/low air circulation
  • Cool temperatures

So, to treat/prevent fungus on your cannabis, you have to make sure to keep these elements out of your growroom/area. This won’t prevent fungus spores getting on your plant, but it will prevent them from growing and evolving into a true infection. If you are too late for prevention, and a plant is infected, you could still change the environment of your growroom to treat the problem.

When growing cannabis, you need to watch out for 3 types of fungus/mold:


Bud rot

Probably the most common type of mold found on cannabis plants is called “bud rot” or “botrytis cinerea” . Bud rot is very persistent and could spread quickly so once detected, it’s important to start treating it immediately.

This type of mold starts to grow from within developed and dense buds. So recognizing the first signs could be tricky sometimes. It quickly spreads to the rest of te bud and is able to ruin your whole crop. Bud rot is only able to survive in very specific circumstances, so treating it can only be done by changing these circumstances.

Bud rot in a pretty late stage, most of the bud is useless now.

Bud rot is a type of fungus/mold. So to infect another plant it releases it’s spores. After release, these spores fly through the air and might land on your plant (our air is filled with different types of spores, so avoiding them is extremely hard). However this doesn’t mean your plant will be affected by bud rot, a spore only develops to bud-rot if it lives in a very specific environment.

These spores makes this pest very contagious. Only one spore landing on your plant can be enough to eventually destroy it. Next to that, you can be a transmitter yourself if these spores are brought in the growroom by your clothing or hands (happens often). If you are removing/cutting aways some parts of an infected plant, be carefull and make sure the scissors or rot doesn’t touch any healthy part of the plant!

More about recognizing and treatment of bud rot!


White powdery mildew

Another type of fungus that is often found on cannabis plants is called “White powdery mildew” (often referred to as “WPM”). This pest will affect your plant in both the Vegetative and Flowering phase and is able to spread quickly once it’s spores landed on the plant.

WPM is found on all kind of plants, so you might had to deal with it before. Compared to other types of fungus, this one is easy to recognize and treat. However you still need to act quickly and good once you detect it. WPM will first appear on multiple leafs and looks as if a layer of flower/dust is poured on them. This layer starts with a few small spots and eventually spread, and take over complete leafs. Just like any other Fungal pest, it’s important to start treating once the first signs appear.

“WPM” takes over a flowering cannabis plant. The white fungal growth will get thicker and spread to more leafs. Eventually, the WPM will block sun from reaching the plant and kills it. “WPM” will also ruin your buds once it reaches there. Never smoke buds that are infected with any type of fungus!

The treatment of WPM can be done by changing the environment in your growroom. Just like bud-rot, WPM loves a cold, moist environment with bad ventilation. By changing these circumstances, you will make it hard for WPM to stay alive. Next to that, you are able to make your own treatment solution or use an organic pesticide to sprays and kill the White Powdery Mildew.

Click here to find out how to recognize and treat “WPM” 


Root rot

Root rot is another stubborn  type of fungus that you often see on cannabis plants. It attacks only the roots of your plant which sometimes makes it pretty hard to detect it on time. This type of fungus can be quite harmfull because it destroys the roots which blocks the supply of water, oxygen and nutrients to the plant.

Roots that are suffering from root rot often looks like brownish, soft and soggy roots. They really get mushy and could fall apart with a little force. Root rot could affect all the roots or just parts of the roots bundle. A plant that is suffering from root rot will show un-healthy, curled up leaves and will look “droopy”. This is the result of an oxygen shortage that occurs when leaves are dead.

Overwatering your plants + a hot, moist environment are the number one cause of root rot. So always try to avoid this and check your soil properly. Next to that, there are quite some options to help you get rid of it. Think about special bacteria, root powder, lots of oxygen/bubble (hydro set-up).

More about recognizing and treating root rot