Has anyone tried Bonsai Mixes (usually fine bark, fine lava-rock & turface). It seems to drain well for Bonsai roots and is a good choice for a wide variety of cuttings, so it seems a natural choice (to me) for orchids.
The Bonsai guys, cut roots off extensively and then encourage new root growth.
I've never seen anyone grow orchids in Bonsai mix or heard any discussion, is it just a cost factor?