This is our general potting medium (1.25 cu. ft. bag) that works well for most orchid varieties. Use the medium grade for plants in 3.25" pots and larger. A hobby bag of mix is generally enough medium to fill about five 6" pots. Our mix is made of clean sterilized Rexius brand douglas fir bark which has been presoaked for 24 hours and then blended with charcoal and perlite or sponge rok. If the mix is not used within 3 weeks of arrival pour into a box and let it dry out. Re-soak before using. Approx. FedEx Ground shipping charge on 1 hobby bag: $10-12, 1 large 1.25 cu ft bag: $15-20, depending on region.