it depends what's your temp in your grow room when lights out? then if you need them go ahead i have it running 24/7 for stem strength. Let me know im here to answer some of the questions to the best of my knowledge without being a complete dick like some people on here man. brother
Depends on amount of plants...air movement isn't just for heat removal or stem strength... what the plant breaths out is toxic to them.... if you have whack o plants you want air movement.. a few plants will be fine w/out fans in dark.. thats why in large grows you see co2 added and scrubbers used to remove bad air/orders......
leave the fan blowing all the time.. i always keep an oscilating fan going in my grow room.. it helps strengthen stems.. moves air so the plants have fresh air to breath.. it even helps keep pests away.. most pests dont like constant wind because its harder to hold onto the plant.. its up to you what you want to do... but i have great success running my fans all the time... check out my grow if you want... journal links below in my sig...
Ok thanks for the help guys. I was asking due to my plants are around 3 1/2 weeks old and i was told their stems are lookin a little thin and that i needed to thicken them up some, and also i only have 5 plants well only 5 in my grow area and i have 1 far away hidden outside. Thinks for the feedback those were the answers i was looking for.
Yea. I only have 1 small fan blowing on them and every now and then ill also have a window fan blowing on them. I would keep the window fan there with the small fan blowing on them but then i would be fighting the person who's fan it is for taking it lol so yea.