Oyster Shell is a natural organic source of calcium and trace minerals for calcium loving orchids. It is 96% calcium carbonate, a gentle source of elemental calcium. Use as a topdressing and replace when gone. The variable particle size allows for immediate and long term release. Oyster shell is basic and is used to raise pH in orchid mix. To test pH we offer a convenient and easy-to-use pH Test Strip Kit.
We recommend you store oyster shell in a cool dry place.