In their natural habitat, epiphytic orchids extend their roots almost freely into the air. ... This explains why orchid substrate isn't actually a soil mix, but a special growing medium consisting mainly of pine or stone pine bark.

What is the best substrate for orchids?

Fir and Monterey bark is the most commonly used potting media for orchids. It is long-lasting, porous, and free-draining. Clay pellets are commonly added to mixes to prevent compaction and add drainage.

What can I use for orchid substrate?

For the main potting material, you can use either ground coastal redwood bark, ground Douglas fir bark, or Osmunda tree fern fiber. All these materials are coarse, and they allow air to circulate naturally around the roots of your orchid.