Agree with the above. It sounds like a plumbing issue. No need to make your plants suffer, however. Seems like hand -misting is the simplest answer as well as pebbled trays below the play to hold a bit of water. I like the mini greenhouse being indoors idea. Erecting a piece of plastic sheeting over the top of your plants so that it doesn't touch them using a frame of sorts. ...pvc, an old umbrella, perhaps? would help keep the plants happy. Keep us posted.
