Late flower RH targets that actually matter outdoors

Once you're three weeks from harvest, your humidity tolerance drops to near zero. I'm not exaggerating. At that point bud density is working against you, and any RH sitting above 55% overnight is an invitation for botrytis to start inside the cola where you won't see it until it's too late.

The targets I shoot for in late flower: below 50% RH during the day, below 45% at night if I can manage it. Outdoors in the PNW that's not always realistic, so the backup plan is airflow. I run a small clip fan on a timer overnight pointed at the canopy, and I hand-strip any leaves that are pressed tight against developing buds. That air gap matters more than people think.

Morning is when I lose the most plants if I'm not paying attention. Dew settles, temps drop, humidity spikes before the sun burns it off. If your forecast shows consecutive overnight lows under 50F with high humidity, that's your warning window. I bring portable shelter tarps or a temporary low tunnel over my girls those nights.

Anyways, the thing growers underestimate is that you can have a clean, healthy plant at week five of flower and lose it in eight days if the weather turns. Check your colas from the inside out, not just the surface. Squeeze gently at the base of big buds every few days. If something feels soft or smells off, cut it out immediately and check the neighboring colas.