I have so far never had a problem with humidity (or maybe i have and i don't know about it) I have never had mold or anything. I used the same closet to dry my buds as I did to grow them. All I used was a large fan. (no fan or on low during drying) I don't think a dehumidifier is really necessary unless you are doing a big grow or are really trying to do everything proper. Or like the first guy said, if you have a humidity problem, ie a basement. Just look for sweat on the walls, if there is sweat or it feels damp in there, probably need a humidifier lol.