Late flower humidity targets before you lose a cola

If you are running outdoor in the PNW or anywhere with wet falls, the window between week 6 and harvest is where mold wins. Botrytis does not wait for you to notice it. By the time you see the grey fuzz the damage is already inside the bud. You need to be watching your overnight humidity like it is your job right now. The number i push for in late flower is 45 to 50% RH during dark hours. Daytime with airflow you can tolerate higher, but those cool damp nights are the kill zone. If you have a cheap data logger sitting in your tent or near your canopy, pull the overnight low temps and RH every morning. Two consecutive nights above 65% RH and dense buds, you are gambling. Airflow matters more than most people realize at this stage. I thin interior bud sites aggressively around week 5 outdoors, not for yield, just to let air move through the canopy. A dense uncirculated cola in September here is basically a petri dish. Anyways, defoliation debates aside, the airflow argument is not really debatable in a maritime climate. If rain is incoming and harvest is close, within 7 to 10 days, i pull early. A 95% mature bud you harvested dry beats a perfect bud you let sit through three days of rain. Running Zkittlez and a couple other 8 week strains specifically because i can get them down before the October rains really settle in. Timing your genetics to your climate is its own form of mold prevention.

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Experienced7d ago

The early pull advice is solid but i'd push back a little on the 45-50% RH target being universal. Dense, resinous buds with thick calyx structure hold moisture way longer than an airy sativa-dom pheno would, so that number is really a starting point not a ceiling. I've had runs where a particularly tight gassy pheno needed me down to 42% overnight to feel safe, while a looser fruity expression on the same strain was totally fine at 52. The thing nobody really talks about is how the terpene profile actually signals stress before you see botrytis. When i'm checking colas in late flower i'm smelling them every single day. A healthy loud terp expression, like that sharp diesel or ripe fruit punch smell, starts to go flat or gets a weird wet hay undertone right before conditions tip toward mold. That's been a more reliable early warning for me than any data logger reading honestly. Not saying ditch the logger, run both, but your nose is underrated in this conversation. On timing genetics to climate, 100%. That's the real long game move.