Sponge Rock is commonly referred to as perlite, and has a wide range of applications that will always be in demand. Clean and lightweight, this material can be incorporated into your favorite orchid growing media.
Used to improve the drainage and aeration of growing media, Sponge Rock is a porous, lightweight, expanded volcanic rock. Its high porosity makes it a good aggregate in potting and germination mixes.
Crystal-white, super-coarse grade perlite.
"#3 Coarse" averages 1/8"- 3/8" dia.
"#4 Extra Coarse" averages 1/4" - 5/8" dia.