Does rain lessen the potency of buds? Can you shake marijuana plants post-rain to ward off mold? Is there a surefire way to avoid mold?
Rained-on buds face two major issues. The first issue is that the glands can be knocked off by wind and rain. Occasionally, only the gland heads can fall off, but these have most of the THC. This will occur as the buds start to reach maturity. Debris from the rain and wind can also be knocked onto the surfaces where they are then caught up in the adhesive glands.
A second (and indirect) issue with the rain is that the moisture promotes fungus and mold growth. The tight buds can take in drops of rain that remain there indefinitely. The dark, moist, and acidic area promotes perfect conditions for the growth of mold. You can keep mold from growing on the buds in a number of ways. Mold likes environments that are acidic, but stays away from alkaline ones. You can make the pH more alkaline by spraying it with water adjusted to around pH 8. You can do this with pH Up or potassium bicarbonate. Mold will not infect the plants until rain washes these products away. Alkaline water is ideal because it does not leave any toxic remainder and will not harm the marijuana plant. Gently shake the buds to remove any of the alkaline water from the surface.