A bud rot check is a deliberate inspection of buds for mould, mainly grey mould caused by Botrytis cinerea, which rots dense flowers from the inside out. It belongs in late flower, at harvest, during the dry and in the first weeks of the cure, because the fungus thrives in humid, still air and tightly packed buds.
In practice
What to look for:
- a single sugar leaf or bract cluster turning dry, brown or grey while the rest is green;
- soft, mushy, brown tissue inside a cola near the stem;
- grey, fuzzy growth, sometimes with dusty spores;
- a musty or damp smell in the room or a jar.
How to check: gently part the largest colas, especially top colas and buds near the stem, and look in at the core. Use a loupe on suspicious spots. In jars, empty a sample of buds onto a tray rather than looking through the glass.
If you find it, cut the affected bud out with a margin, bag it inside the room to avoid spreading spores, and don't smoke or process mouldy material. Then fix the cause: RH in late flower around 40-50%, air through the canopy, a drying room at about 55-62% RH, not higher.
Don't confuse with
- Powdery mildew: white powder on leaf surfaces.
- Natural senescence: yellowing leaves, not brown, mushy buds.
- Pistil browning: normal ageing of stigmas.
Botrytis cinerea, the fungus behind bud rot or grey mould, which rots dense colas from the inside in cool, humid conditions late in flower.A small leaf growing from within the flower cluster, often coated in trichomes, which is trimmed off and commonly kept for processing.The dense, elongated cluster of flowers that forms at the end of a stem or branch; the main cola tops the leader.Relative humidity is the water vapour in air as a percentage of what it could hold at that temperature, so the same RH dries plants differently at different temperatures.A dark, ventilated space where freshly harvested cannabis is dried under controlled temperature, humidity and gentle airflow, usually for 7-14 days.A fungal disease, on cannabis caused mainly by Golovinomyces ambrosiae, that grows as white powdery patches on leaves and buds and thrives in moderate humidity.The programmed ageing and breakdown of leaves and other tissues, in which the plant recycles nutrients (especially nitrogen) from old leaves to developing flowers and seeds.The female reproductive organ of a flower (ovary, style and stigmas); in cannabis growers loosely call the visible white stigmas "pistils".Holding dried cannabis in sealed containers so its moisture declines slowly and evenly over weeks, improving smoothness and aroma.A small handheld magnifier, typically 30-60x for cannabis use, used to inspect trichome heads and spot pests and male flowers.
