Can you give us a little more info so we can answer your question? How big is the room? Is the current humidity too high or too low? Temps? Heaters or no? Lighting? Venting? Soil or hydro? Tell us how your growing and we can prolly help...
Sorry for being so vague. My grow room is the size of a medium sized shed, my actual grow space is 4' x 5'. The current humidity is 70% and i'm currently flowering (I know I've heard it before, bud rot ,etc. etc., which is pretty much why i'm asking now) therefore my humidity is to high. My temperatures stay between 70-80 with one heater. For lighting I use a 600 watt HPS with 28 watt t5 supplemental lighting. For ventilation I have a 6 inch inline fan and passive intake with an oscillating fan that helps move fresh air inside. For growing mediums I have a little half half thing going on, 4x5 gallon dwc buckets and 3 soil. Looking forward to any suggestions on how to control my humidity levels! -Thanks!
I would try to get more air moving thru the room by adding an intake fan and maybe even another exhaust fan...that's if the ambient intake air is not too humid and would add to the problem. You might have to run a dehumidifier if that's not enough. Fans are relatively cheap tho, so that's where I'd start.
A dehumidifier of course. It's not an expenive investment, $50 for the cheaper portable units, and they don't take up that much room, or use that much energy. To eBay now, go go go!