Bud Rot or Mold
Example of cannabis bud rot
Cannabis bud rot (aka “Big Bud Disease” or “The Curse of the Successful Grower”) attacks your fattest, biggest buds right as they start to approach harvest time.
Too cruel… Bud rot attacks and kills your biggest, thickest buds. Often the first sign of cannabis bud rot is the surrounding leaves turn yellow suddenly (over the course of 1-2 days). The base of these discolored leaves is where the bud is rotting.
by Nebula Haze
How to Prevent & Stop Bud Rot (quick summary)
Avoid wet buds & high humidity – Bud rot is a fungus, and like all fungi, it needs a wet place to germinate and grow. About 40-50% RH is ideal for the cannabis flowering stage, and over 60% RH invites bud rot and mold. Don’t allow buds to sit in damp or overly humid conditions for long. Indoor growers can use a strong dehumidifier to reduce humidity in the grow space if necessary. Outdoor growers can cover plants when it rains and shake them off when they’re wet. Another strategy for outdoor growers is to get short-flowering (ex: Pineapple Express #2) or auto-flowering (ex: Purple Punch Auto) strains so their plants are ready to harvest before the start of the local rainy season.
Great air circulation – Air should be moving over the buds and leaves as well as through the plant. Fans are a huge help indoors, especially if you set up an exhaust fan to vent hot humid air away from your plants. Oscillating fans can help prevent humid spots but only blow air around so they can’t lower the overall humidity. Outdoor growers can move potted plants to a breezier location but if plants are in the ground, unfortunately, there’s not much you can do to increase air circulation.
Defoliate extremely bushy plants – Each leaf is constantly adding water vapor to the air. That means removing leaves can help lower the humidity through and around the plant, especially in a small growing space. If you decide to defoliate because plants are covered in tons of leaves and the humidity is high, remove leaves that aren’t getting much light (typically the middle and bottom of the plant) since they aren’t making food for the plant anyway.
Watch long, dense buds for signs of discoloration – Almost like a cruel joke, bud rot usually attacks your biggest colas 🙁 That’s why cannabis bud rot is sometimes known as “The Curse of the Successful Grower”
Remove all buds affected by bud rot immediately – Carefully remove and discard all buds with bud rot, as well as nearby buds. This is a fungus that can spread quickly. Don’t let any of the dusty rot touch other parts of your plant to avoid spreading mold spores.
Consider harvesting early – If you can’t fix the environmental conditions that caused the bud rot (for example if it’s wet or humid and you can’t do anything about it), I highly recommend harvesting plants early to avoid further losses.
