How to Rid Your Cannabis Plant of Bud Rot

Are You Ready to Start Growing Yourself?

If you're ready to start growing and want to find out the best seedbanks that ship to the U.S. click here.

In Common Marijuana Insects and Pests to Look Out For we mentioned that bud rot is one of the most common diseases that plague marijuana. Also called “grey rot” this mold is also one of the most sinister, it’s truly disheartening to see your buds suddenly waste away before your eyes after months of hard work. However, bud rot isn’t inevitable, you can totally prevent and even stop it in its tracks as long as you take good care of your plants and observe proper preventive measures. 

How to identify bud rot

Bud rot or Botrytis cinerea is a kind of fungus that attacks the densest parts of the plant. It is a systemic disease that often makes its way through openings in the plant tissue. What’s so difficult about dealing with bud rot is that your plant can already be rotting on the inside even though it still looks ok on the outside. However, there are telltale signs of a bud rot infestation, the most obvious being the white or grey wisps of mold on your buds. But by the time you see this, the infected bud is already a goner and needs to be removed.

Bud rot will typically target the biggest buds on your plant since large colas have a bigger space inside that is almost always moist, a perfect breeding ground for the fungus. 

If you think your plant already has bud rot, don’t hesitate to cut off all the affected parts. If you leave it on its own, bud rot will consume 

Why is bud rot bad

Growers fear bud rot because it is practically an invisible enemy that eats your plant from the inside. It will only make itself known when your plant already shows signs of damage. Worse yet, there’s no cure for bud rot so even after you’ve identified it, the only thing you can do is to prune and discard the infected parts of your plant.

When you might notice bud rot

Bud rot has an incubation period of 18 to 30 days so by the time you notice it on your buds, your plant’s tissues are already filled with its mycelial network for quite some time. Because it only fully manifests itself during the flowering stage, bud rot is so difficult to spot which is why stringent preventive measures are your best bet against it. Once your plants catch it, there’s nothing left to do except to cut off everything to prevent it from spreading.

Initially, you may also notice that some of your plant’s leaves are wilting and turning brown. This is because the inside of the stem they are attached to is already turning into mush. These stems will also be soft and prone to breakage.  

Meanwhile, buds that have caught the spores may appear to be drying up on the outside with some of the bud leaves turning brown and curling up. You’ll also notice some white fluffy mold growth on certain areas of the bud. Eventually, these buds will develop some dark mushy spots where the rot will come out. 

It’s best to cuff off any part of your plant that you suspect to have bud rot. It can completely infect a single plant in just around 36 hours and can spread like wildfire to your other plants. Since bud rot spores are airborne, you should contain each infected part with a plastic bag and carefully prune to prevent the bud from accidentally dusting off on other plants.  

Organic methods to deal with bud rot

Unfortunately, there is no way to treat bud rot once your plant catches it. As mentioned earlier, it is a systemic disease and there is no way to wash it off your buds. Don’t even attempt to smoke or use infected buds for extraction, it will only make you sick.

However, this disease is totally preventable. Here are some of the measures you can take to avoid catching bud rot in your grow space:

  • Maintain correct humidity levels and enough airflow – Bud rot and mold in general thrive in warm and humid environments so you should closely monitor your RH levels using a digital hygrometer, which is an indispensable gadget for all cannabis growers. If you live in an area where humidity levels rise above 55 percent, you should get a dehumidifier for your grow room. You should also maintain adequate airflow between your plants, this will also help regulate the temperature and humidity within the area. Proper pruning and training will also give your plants more space for air to circulate. 

  • Keep everything clean – Since this disease is airborne, it’s very possible that you or your pet can carry it into your grow area. This is why you should sanitize everything that may come in close contact with your plants. Using a sterilized growing medium, cleaning your tools, changing your clothes before entering your grow room and keeping your pets away from your plants are just some of the steps you can take to minimize the risk of bud rot. Use a fungicidal soap for washing and sprays for your grow room walls and floor. However, keep in mind that a strong scent will affect the smell and taste of your buds so use disinfectants only when needed. Having an air purifier specifically designed to get rid of mold will also serve as an extra layer of precaution.

  • Neem oil, bicarbonate spray and beneficial bacteria – You can also prevent or slow the spread of bud rot using bacillus subtilis, a kind of probiotic bacteria. This is often mixed with neem oil which is a popular organic pesticide that also gets rid of common cannabis pests. You can also try using a Potassium Bicarbonate (KHCO3) spray, a popular cannabis fungicide.
Durban Poison
  • Choose a mold-resistant strain – Some cannabis strains are naturally more resistant to molds than others. Some are more suited to wetter climates while others do well in warmer ones. You should consider the natural climate and seasonal changes in your area when choosing a strain to grow, unless you can maintain a constant, ideal growing environment in your grow room for the strain of your choice. One such strain is the Durban Poison which originated from humid regions of South Africa.

Non-organic methods to deal with bud rot

Since bud rot is systemic, fungicide sprays will be ineffective against it. However, some growers do try fungicides to try and salvage their plants. You should never ever do this, consuming fungicide-treated moldy buds can make you terribly ill, give you permanent health issues or even kill you. Eagle 20 (Myclobutanil) is one such example of a fungicide that has already been banned for use on cannabis.

Frequently Asked Question on Bud Rot

How fast do bud rot reproduce?

Bud rot or Botrytis has an incubation period of around 10 or more days. Once symptoms are visible, it can only two or more days for the mold to kill the plant completely.

What are signs that you have a bud rot infestation?

The most obvious sign of a bud rot infestation is the wispy white mold growth on the buds. The buds may also show some dark mushy spots and its leaves may turn brown and curl up.

Is bud rot harmful to cannabis plants?

Bud rot or botrytis is one of the worst diseases that can strike your marijuana since it is systemic and cannot be treated by fungicides. The only way to get rid of bud rot would be to cut off the affected buds and prevent the mold spores from settling on your other plants.


Bud rot and other molds are diseases that will really test your mettle as a cannabis grower. Don’t get complacent if you haven’t experienced it yet, just maintain or strengthen your preventive measures because by doing so, you will also stop other diseases and pests from attacking your plants. If you have the budget, invest in a good air purifier and dehumidifier. Keeping your grow room and surrounding areas clean and sanitized at all times will also go a long way and save you the heartache of having months of hard work go down the drain. 

Thinking About Growing Your Own?

Check out this post where I go into the details about equipment, seeds and the reasons why I got started in this journey.

Leave a Comment