Always have a fan blowing gently on the plants to circulate air and build strong stems. Theres is no timer, you can have it blowing on them 24/7 (gently).
What about my grow, cretin? Do you think I should run my exhaust fan, which causes enough flow to gently move the plants, 24/7? Currently, I run it on the same schedule as my lights, to ventlate heat. I've got strong stalk. All I really see it doing is unnecesarily spreading the stink. I definately agree that young plants should have 24/7 wind, but what about well established plants?
It will make it stink less at ground zero, but it will ventilate the odour farther around. My grow is in a wall unit in my bedroom. With the exhaust fan on... the stink leaves the box, enters my room, and starts exiting my room through the door and the vents.
Leave the fan on, the exhaust fan only needs to be on during lights on, unless your concered with a little odor.