Orchids are not as difficult to grow as many people imagine. While they have a different set of cultural needs, they also adapt well to the environment of the average home, provided that their most basic needs are carefully met. These needs include proper daytime and nighttime temperatures, proper fertilization and, most important, water. Orchids commonly grow high in the trees of the world’s rain forests, so the potting medium you choose for your orchid matters only in its ability to support the plant and to hold water.
Most orchids are epiphytes, also known as "air plants," and they grow on the branches of trees in the rain forest. In fact, orchids do not grow in soil at all. Regular potting soil will block water drainage and cut off air circulation to the orchid’s roots and quickly kill it.
The potting medium you choose for your orchid should support it enough so it does not fall over. It should absorb enough water to keep the medium moist. Some of the most popular potting media for orchids are Osmunda fiber, a fern native to Australia and the South Pacific, whose tough, wiry fibers break down slowly; and fresh pine bark, which is often mixed with other media.
Other potting media are sifted perlite, peat moss, fir bark chips, redwood bark tips, tree fern fiber, coconut fiber, coconut chips, granular charcoal, expanded clay pellets and rockwool, according to orchids.com. It is possible to use mixed media to achieve the best water absorption and drainage for your orchid.
It’s a good idea to join an orchid club or to check with growers and breeders in your area to see which potting medium they prefer. Different regional climates might demand different mixtures of potting media.
Because the potting medium provides no nutrients at all, regular monthly fertilization–at half the recommended rate–is necessary. For the best results, choose a water-soluble fertilizer made especially for orchids.
Different cultivars require different amounts of water. Orchids are adapted to conserve water, but the most common cause of orchid death is improper watering.