Hi Anne, noone's saying anything so I guess you get "Mr. mouth, haha.
Most of the orchids you find at the store or website are almost always
in spragum moss or bark. The ochid I got the other day was in moss,
very tight moss. I repotted it in moss around the healthy root (perfect
for damp and dry effect) and then half and half the rest of the way.
You might try lava rock, but it seems so rough, if your plant gets
moved, even once, how will it's roots like all those lava rocks grinding
together? Just a thought. I heard they put rocks in the bottom of
plastic pots for weight. Good luck.......me