Concerned about humidity problems in my grow area

[dougroc]

My grow area is a recessed window seat area the faces a south window and has a bank of four t5 HO flourescents above it that supplement the often meager light we get in our winters here in Rochester, NY. I am using pebble trays to help raise the humidity, and they seem to work because my digital humidity meter reads around 40% on average. On a sunny day the humidity may drop to 30% and on a cool night it can reach 50%.

I was thinking of raising the humidity a little more by adding a room humidifier to the area, however I was concerned that I might get mold on the drywall. Has anyone else had such a problem, or is my concern unwarranted? Right now the only issue with the humidity it the amount of condensation on the window glass, which I guess could cause the paint on the window frame to peel.

Any thoughts?

[mycologist]

I have used humidifiers throughout the house with no mold problems for years. The window condensation is an issue because the glass is so cold, but insulated walls should not develop condensation if you use a reasonable size humidifier for the room. Mold takes >70% usually. I just bought a new one today to replace the one my wife stole back from my grow area.

[JoeW]

The EPA suggests that maintaining an indoor humidity ranging from 30% to 60% reduces the risk that mold might develop. Source: Mold Resources | Mold | Indoor Air Quality | Air | US EPA
The minimum relative humidity permitting growth of mold varies from 75% to 95%... protection of materials is assured only if the atmosphere is below 75% relative humidity. Source: http://www.pubmedcentral.nih.gov/pag...28&pageindex=1

[Lambert]

My grow area is a recessed south facing window as well and I have a humidifier on 24/7 in the fall/winter and manage a constant 60% humidity (sometimes slightly less sometimes slightly more) without any side effects.
I leave the doors open for ventilation.