Sun Bulb 5002 Better-Gro Special Orchid Mix, 8 Quarts Special orchid mix It is a rich mixture of western fir bark, hardwood charcoal, and sponge rock to ensure healthy and long-lasting plants It is a multi-purpose mixture that is appropriate for all epiphytic orchids Provides your orchids with the drainage, air flow, and root ventilation they find and thrive on in nature Should be used when re-potting your orchid, at least every 12-18 months or as needed to support healthy growth