Dear All, My compost for epipytic cacti and epiphytic Hippeastrum is made of roughly equal parts of the given composted wood, perlite and/or seramis and commercial peat based potting compost of good quality. It has to "feel and look good" when I mix it. It is not a standardized mix because the composted wood differs according to the grade of branches shredded and the variety of wood but it is very good. I should add that I grow my epiphytic Hippeastrums in clay pots whereas I grow all other bulbs in plastic containers. With plastic in Hippeastrums I find often too much moisture that cannot escape through the walls of plasctic pots but will do so with clay. Uli