Do Orchids Need Special Soil?

Soil for Epiphytic Orchids

• Epiphytic orchids are tropical plants that can often be found growing on the sides of trees in rainforest environments. These types of orchids use long, modified aerial roots with a spongy epidermis to absorb humidity and nutrients from their surroundings. When grown indoors as houseplants, epiphytic orchids need loose, coarse and well-draining soil mix that won't smother their roots. Commercial orchid potting mixes are available or you can create your own by combining equal parts sphagnum peat moss, chopped tree fern fiber, redwood bark, coarse horticultural sand and granulated charcoal.

Epiphytic Orchid Culture

• Plant the epiphytic orchid in a well-draining planting container, preferably one with vertical drainage slits in the sides. Position your orchid where it can receive bright, indirect sunlight for at least four hours each day; this will help to ensure that it has the energy it needs to produce its characteristic blooms. Provide daytime temperatures between 70 and 80 degrees Fahrenheit; lower the temperature to between 60 and 65 F. at night. Water the orchid once a week using the ice cube watering method recommended by Just Add Ice Orchids; position three ice cubes on the surface of the soil mix and allow them to melt. Fertilize your orchid once each week while the plant is actively growing; use a quarter-strength application of a specially formulated orchid fertilizer, applied according to label instructions.

Soil for Terrestrial Orchids

• Unlike their epiphytic counterparts, terrestrial orchids can be grown in the soil found in most gardens and home landscapes. Though they aren't picky when it comes to soil type, terrestrial orchids do insist on soil that's well-draining. Enriching the soil at your planting site with organic materials will help to improve its drainage. Use a garden tiller to incorporate 3 inches of equal parts sphagnum peat moss, perlite and coarse horticultural sand into the top 8 to 10 inches of soil.

Terrestrial Orchid Culture

• Most terrestrial orchid species can be cultivated outdoors in United States Department of Agriculture plant hardiness zones 4 through 10; consult the care information for your individual species to determine the appropriate hardiness zones. Plant terrestrial orchids in partial sun locations that are shaded during the warmest parts of the day. Provide the orchids with 1 inch of supplemental irrigation each week while the plants are actively growing. Though terrestrial orchids require very little fertilizer they can benefit from an application of alfalfa meal fertilizer each spring at the beginning of the growing season. Apply alfalfa meal fertilizer according to package directions.