Tonette,

For plain old fashioned rock, you can simply go to Home Depot or Lowes and
pick up "river rock" in whatever size you need. As with any stone, it needs
to be rinsed before using. At those locally based stores you can usually
also find charcoal and lava rock. For high quality spaghnum moss, or
aliflor, or spongerock, you'll need to either visit your orchid grower or
order online, as Pam said.

Diana