Add up to 30% GRODAN Grow-Cubes™ to bark for a great orchid mix. Also try mixing Gro-Wool™ (absorbent granulate) with perlite to create your own perfect orchid mix. Some suggestions (found on Harvey’s Orchid Notebook online): 60% absorbent for epiphytes, but more absorbent for other types of orchids. Also, mix with Styrofoam (peanuts near bottom, smaller near top), 7 parts to 3 parts of stone wool, plus fine or medium bark and perlite (brings pH down from 8 to 5) (recipe is as follows: 2 parts fine or medium bark, 2 parts medium grade absorbent stone wool, 3 parts perlite, 7 parts fine (peas size) Styrofoam and lots of water). Also-50/50 stone wool to perlite. Use your imagination to devise the best mix for the precise type of orchid you are growing.