Do I need special soil?

You need a loose, open soil that remain wet to moist but allows drainage of
excess water. Try one part of each of the following; long-fibered sphagnum,
peat moss, perlite, pumice, lava rock, vermiculite, fine orchid bark, and
charcoal. Or try one part peat or long-fibered sphagnum, one part fine orchid
bark, one part perlite, one part vermiculite. One part sphagnum to two parts
osmunda fiber is acceptable. The same mixes may be used for many terresterial
orchids.