I spray mine with water about ONCE or TWICE in flower. They get the freaking drenching treatment about week four of midflower, and only to knock the dust off. As for needing to spray, nope you dont. In fact, you are risking mold and other issues by misting them. Id reccomend to NOT BOTHER misting often, because its a risk that doesnt give you much if any gains....unless its to cleanse the plant matter. Yes, it rains outside, but I also think the lighting and breeze is a tad different. Just my observation. MJ leaves seem to change in anticipation of lighting, to perspire or conserve water, and i think the leaves are designed to give the plant a bigger "footprint", to help direct more water to the soil underneath and catch more energy (light). Not so sure they turn over to get the bottoms wet. Happy growing!