I've only ever had problems with extra humidity, not lack of! And it's dry as a mofo up here in wintertime. The air crackles with static. But maybe I've just been lucky, who knows? Normally I have to watch for damping off in seedling stage, and then mold in flowering. Maybe I tend to grow strains that like things dry, I don't know.

EDIT: How come some of the plants are bright yellow? Or is that the lighting? hahah.