One version (there are several) consists of 57% fir bark, 32% coarse peat (poultry grade) 5% Palco wool (redwood fiber), 6% coarse Perlite; to each cu. ft. add 4 lbs. bone meal, 1/2 lb. superphosphate, 1/4 lb. ureaform nitrogen and 1.5 lbs. of green sand (Glauconite) if you can get it. The orchid doctor, page 88, this and other versions.