Once bud rot has taken hold over parts of a cannabis plant, the buds can sometimes look almost the same on the outside, at first, but they usually start looking like they’re dying in patches. Often the area will dry out and easily pull apart. The inside of buds can turn brown, gray or even purple.
If your plants are never exposed to these spores, they will never get bud rot.
As soon as even one part of a single bud starts showing signs of grey mold, the rot can spread to the rest of the cola and then to other buds on the plant. If triggering conditions (lack of airflow, wetness) have not improved, a single point of infection can quickly ruin the harvest of an entire plant.
What Does Bud Rot Look Like?
Bud Rot needs warm, humid conditions and stagnant air to thrive.
Did you know? In addition to cannabis bud rot, Botrytis causes problems for many different types of plants, including wine grapes, strawberries and peonies.
Here’s how to fix the environment:
In addition to the rot itself, you may see white mold on the outside of the bud at first – this is the first stage and it means plants need to be treated immediately! With advanced bud rot, the bud will easily separate so you can see inside. When the bud in question is inspected, it will be dark on the inside, usually gray or brown, and possibly dusty (this “dust” is fungus spores).
Some growers might think these drying spots mean that the plant is almost ready for harvest, but you know something is definitely wrong when just parts of the colas are being affected.
Bud rot is a mold that develops in the thickest parts of cannabis buds. Read for more information on how to prevent and solve bud rot before spreading!
Indoors, getting a dehumidifier will help, even is if is a simple one with crystals that absorb moisture from the air rather than a big one that must be plugged in. It is worth investing in a hygrometer to measure the relative humidity inside a growroom.
The optimum humidity varies depending on what stage of life the plants are in. For vegetation, it should be between 40% – 70%; during early and mid flowering, it drops to 40% – 50%; in the final stages of flowering, less than 40% will help to prevent cannabis moulds and powdery mildew.
Not only is it very unhealthy to inhale or consume the spores, if they are left on the plant then the same problems will continue.
Some are more resistant, such as the Early Skunk. For growers without much experience, choosing a hardy, mould resistant strain is a good idea to give more chance of success.
The best ways to tackle the problem are removing any mulch, straw, or random vegetable matter from around the bottom of the plants, and increasing the airflow around and between the buds, as detailed below. If they are in pots, bringing them to a sheltered, covered place when it is raining is worth trying.
Outdoors, there is obviously little that can be done to decrease the humidity of the air. As the seasons begin to change from summer to autumn, in most climates it is still warm but the rain increases.
If the lack of air movement is above the plants, increase the outflow. If it is below the plants, point oscillating fans at the bottom of them. Outdoors, it is generally impractical to try to point fans at plants. If the plants are in pots, moving them to a more exposed and windy position during the day when it is not raining will help a little.
Unfortunately, by the time that mould is easily visible, invisible mould spores will have contaminated a much larger area. The only way to really get rid of mould, mildew and bud rot on cannabis is amputation; tragic though it is, the parts of the plant that are afflicted must be cut off as soon as the problems have been identified, plus a good area around them to allow for the spores.
To help prevent mould and fungus on cannabis growing either indoors or outdoors, the airflow through the plants and around the buds can be increased by carefully trimming off large fan leaves and any branches without any buds on them.
Curious if you have a case of bud rot? Wondering what mildew looks like? Hoping to avoid creating the ideal conditions for mould? Sensi Seeds tackles the main causes of the main problems, and how to identify them, when it comes to cannabis going bad.