Botrytis, commonly called “bud rot”, is a type of mold that develops on the dense cores of flowers. It starts in the stems and works its way into the base of the flower buds, eventually consuming and destroying the whole flower.
If caught early on, bud rot can be minimized to only a few infected plants, but the only way to get rid of it entirely is to destroy the infected plants and fix your environment.
Botrytis thrives in cooler temperatures with high humidity. If you have no proper airflow in your grow room, your plants can become a breeding ground for bud rot. One of the most common causes of bud rot is a double edged sword for a lot of growers.
As cannabis flowers develop and become more dense, more moisture can collect on the flowers, particularly in more humid environments. While a lot of growers try to produce the heaviest buds possible for higher yields, doing so runs an increased risk of developing bud rot if extra care is not taken.
Bud rot is also much more common in cultivars that grow stockier with denser buds due to their genetics being more accustomed to colder temperatures. European, hemp-derived cultivars grow taller and more airy compared to drug cultivars, which gives them superior mold resistance with more air flow.
An observant grower should be consistently checking their plants, looking under the canopy, and getting into the base of the buds with a loupe to check for botrytis. It isn't easy to catch if you don't know what you're looking for though.
Botrytis can be confused for amber trichomes to an amateur, as it can have a white or brownish color that resembles dark trichomes. But the distinguishing feature of bud rot is the wispy, web-like threads that spread across the bottom of the buds.
Botrytis can be caught before harvest, but more often it's spotted after harvest during trimming. It won’t always affect every plant in the grow, which is why it’s so important to check every plant, and during trimming check all the flowers for bud rot.
Bigger, denser buds are more likely to develop botrytis, so these buds need to be checked first. Simply rotate the flower around, checking the base for the white to dark brown, wispy threads. Squeezing the bud softly and listening for a crunch can also help.
If the bud sort of mushes together in your fingers without crumbling or breaking, there’s a chance it still has moisture in it. If the bud feels a little too sticky, check for bud rot.
The best way to deal with botrytis is to catch it early on, or preventing it all together with environmental controllers that maintain proper temperatures and humidity in the grow. If you do encounter bud rot on your plants, the earlier you get on top of it, the better.
Unfortunately, bud rot is most likely to develop in the later flowering stages as buds get more dense. This means the infected plants need to be thrown out, and the remaining plants moved to a stable grow environment until you get your original environment set up properly.
The harsh reality of botrytis is that when you catch it too late there is nothing you can do. Some growers will cut out the rotted flowers and try to keep the remaining buds that look unaffected, but mold can spread without being visible at first. Just because you don't see anything when you harvest, doesn't mean the consumer won't have to deal with it down the line.
In every case, bud rot equals lost plants and money for a grower, and that's why it sucks. But with proper environmental control and a little help from Cultivate, you can get your grow room set up so you never have to worry about bud rot being an issue.