In my naturally dry High Desert environment I find that many, though not all of my Vandaceous really do need 70% RH or more to perform well and stay healthy. I can maintain this for much of the year, but come late fall or winter between cold temps and high winds I probably average 50% to 60%. Occasionally a bit more humidity and occasionally a bit less. I was watering Twice a day for over a year and a half. Now I mist very heavily X 1 and hours later I dunk water in a very large tub I have for this purpose as my green house floor is not mean't to take large floods of hose water. The misting does increase humidity if only for a few hours each day. I have read many times that Vanda's can do fine on 50% or 60% humidity, but long term I can only say that some do, some don't. This is my experience. If any of you in northern latitudes or dry desert areas have Vanda's were your experience is different from mine, I'd be pleased to hear about it. My green house temps. are 62 degrees F. to 81 degrees F. the year round so there very moderate. Thanks in advance for your input! AL