Stagnant air is where bud rot and powdery mildew start, and uneven airflow creates microclimates that stress some plants while baking others. Gentle, constant canopy movement keeps leaf surfaces dry and temperatures even.

Aim oscillating fans to rustle leaves without bending stems, and add under-canopy circulation in dense flower. Good airflow is one of the cheapest defenses against the most expensive late-cycle losses.