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.
Some strains of cannabis are especially susceptible to these problems, for example the Big Bud, simply because the buds are so large and dense; this is the downside of it being such a high-yielding variety!
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.
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 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.
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.
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.
There are few things worse than lovingly nurturing a crop of cannabis through vegetation and flowering, only to have mould strike in the last weeks before harvest. Unfortunately, this span of time is exactly when the most common types of cannabis rot and mould infections usually occur. Knowing the reasons for this also suggests how to prevent them occurring.
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.
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.
How to Prevent & Stop Bud Rot (quick summary)
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.
Fungicides, Neem Oil & Burning Sulfur
Protect your buds from rain. If you know there will be drizzly conditions, cover your plants with a tarp to protect them from most of the rain. Don’t put tarp directly on plants or you’ll hurt your buds. Install the tarp up above the plants, and make sure it’s held up by the center part, that makes it so rain runs off the sides of the tarp instead of collecting in the middle.
- harvest the cannabis plant now
- let it continue to ripen, but only if you fix the environment
Good air movement – Create good air circulation and make sure there’s always plenty of air moving over all the buds and leaves. Make sure your plants are getting access to cool, fresh air.
When growing outdoors…
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.
Wetness or High Humidity
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!