Orchids are becoming increasingly popular as houseplants. One orchid you are likely to encounter is the Phalaenopsis, or moth orchid. It gets its name from the shape of the flower that resembles a moth in flight.
Moth orchids thrive in medium light. A window with southern exposure is ideal. You will notice that the pot is filled with a bark-type potting mix. In nature, these plants grow on trees, so they need a potting medium that is light and well drained—regular potting soil is not appropriate. The roots are fleshy and covered with a white spongy material. They may grow into the potting mix, around the pot or simply out into the air. This is natural and healthy for the plant.
Water plants thoroughly once the soil has become light and dry. Allow some water to flow through the pot at each watering—be sure to remove the inner pot to the sink when you are watering and allow the pot to thoroughly drain before you place it back into the outer (often decorative) pot. You may also water by placing a few ice cubes on the surface of the potting medium a couple of times each week, just be sure that the plant does not sit in water for more than a few hours. Liquid fertilizer can be applied with the water every two or three applications—follow label directions for how to dilute the fertilizer.
Plants may flower for many months, and individual flowers may last for several weeks. Do not cut the flower stalk back after flowers fade because in a few months it may branch to form additional flowers. Small plantlets may arise on the flower stalk. These plantlets can be potted up, but they will need to grow for a couple of years before they will flower.
Submitted by Rick Durham, Extension Horticulture Specialist, University of Kentucky