Sphagnum moss for Dendrobiums and Cattleya

[scerdena]

I've recently re-potted my Phals and other orchids and have decided to put sphagnum moss on top of the bark (onthe phals) to prevent the new roots that are on top of the bark from drying out. Is this the correct thing to do? Or is it better for me to just mist the exposed roots daily? I've read here that it is okay to do this with the Phals, but what about the dendrobiums and new roots on the Cattleyas? Can I do the same with them or is it better to just let the roots take to the air?

Thanks for your help. This board is wonderful!
Shirley