While some orchid growers stick with the tried and true potting media of bark or sphagnum, this is not the only way to grow award-winning orchids.  Many orchids are amenable to hydroponic or semi-hydroponic culture.  For semi-hydroponic culture, the medium of choice is perlite.  Click below to read an early article by Wally and Barb Thomas that details their ground-breaking research into growing orchids in perlite.