Even though African violets (Saintpaulia ionantha) and phalaenopsis orchids (Phalaenopsis spp.) Both require well-drained potting mixtures, their growing conditions are too dissimilar for them to do well at precisely the same sort of planting medium. Phalaenopsis orchids, hardy in U.S. Department of Agriculture plant hardiness zones 10 through 12, naturally grow on tree trunks and limbs with their roots exposed. They do not grow well when planted in dirt, even the well-drained land required by African violets, which are hardy in USDA zones 11 through 12.
Phalaenopsis Soil Needs
Potting mixtures for phalaenopsis orchids must provide the sort of air movement that the plants are used to in nature. Most phalaenopsis growing mixtures contain fir bark, which holds little water and is coarse enough to provide air movement. Because orchids also require high levels of humidity and water, fir bark is typically mixed with at least one other substance that absorbs water; examples include chunky sphagnum peat, sphagnum moss, tree fern fiber and perlite. The outcome is a potting mixture very different from African violet soil, which is typically a combination containing 1 part all dirt, perlite and sphagnum peat.