Rock chips

Rock chips are inexpensive, inert and drain well.

Rocks are crushed and screened to sizes from a couple of mm to many cm.

The rock chips used can be anything from bluestone to limestone to granit to metamorphic type rocks, etc. All rocks have low water retention capacity and enhance air circulation.

I do not like using rock chips and avoid buying orchids grown in rock chip filled pots. The reason is very simple: The plants may look very healthy, etc. etc, but I find it very difficult to re-pot them. The roots attach themselves so well to rock chips, especially porous rock chips, that I find it very difficult to separate them without injuring the roots.

Vandatious plants are easier to handle because ot the air roots. I remove from the pot the loose rock chips without disturbing the roots and add cork pieces in their place.

Small pieces can be used, like coarse sand, to top up Perlite or other light media and prevent them from floating away.