Late flower mold window is real, here is what works

We are entering the danger zone out here in the PNW. Nights are dropping, morning dew is sitting on buds longer, and dense late-flower colas are basically sponges. If you are not thinking about mold right now, you are already behind. The number i watch most is the overnight low relative to daytime high. Once that swing gets past 20 degrees, humidity inside the canopy spikes hard at dawn. My target is keeping RH below 50% during those early morning hours. I run a cheap wireless sensor clipped right inside the canopy, not at chest height, not on the fence. In the canopy. Airflow is the other one. Anyways, a lot of people pull leaves for light penetration in flower but forget that airflow matters just as much. I do a pretty aggressive defoliation around week 5 or 6, opening up bud sites so air can actually move through. Stagnant pockets are where botrytis starts. For strains that stack tight, i start hitting them with a potassium bicarbonate spray every 7 to 10 days starting week 4. Last day of application is 3 weeks before my target harvest. Keeps the surface conditions hostile for spore germination without leaving residue on final product. If you see a single brown calyx cluster that looks wet, cut it out same day and bag it before it walks into your grow space. That is not negotiable this time of year.

1 comment

1 Comment

Seedling1d ago

Left Coast here as well. Solid Information. A couple things I also do is; Know Your Microclimate Check weather satellite footage at least 5-7 days in advance. Remove any weeds or unnecessary ground cover because they love to hold moisture.