Late flower humidity targets before the rain hits

If you are pushing into week 6 or 7 of flower outdoors, your humidity tolerance drops fast. Buds are dense now, airflow inside the canopy is poor, and any sustained stretch above 55% RH at night is where botrytis finds its opening. I watch my hygrometer harder in late September than any other time of year.

The target I run is 45 to 50% RH during lights off or overnight, and I want daytime spikes to stay under 60%. Once you see back-to-back nights creeping into the 65 to 70% range, you are on borrowed time with thick colas. This is not abstract, this is where I have lost harvests before getting disciplined about it.

For outdoor growers, anyways, you can not always control the weather but you can control canopy density. I do a hard defoliation pass around week 5, targeting any fan leaves that are blocking airflow through the middle of the plant. Not a strip job, just opening lanes so moisture can move out instead of sitting.

If rain is coming and temps are dropping, that is my cue to get a tarp or a temporary hoop structure over anything that has more than two weeks left. Wet buds that stay wet for 18 hours are a mold event waiting to happen. Early harvest beats a garbage harvest every time.