The only time when you have a fan trained on your plants is if it is in a fixed position because it can cause wind burn. The benefits of having ventilation fans are the following: 1) circulates air; 2) stems tend to strengthen; 3) does not allow a multitude of insects not to land where they can lay eggs.
so is there such a thing as too much air blwing on them...like if the plants are moving around and swaying 24/7......nothing too violwently,.but there not exactly still either..is this fine?