The most commonly available member of the orchid family, the moth orchid (or Phalaenopsis) is not as hard to grow as you might think. It is an exotic, fragile-looking flowering plant available in colours ranging from white, cream, yellow and shades of pink. These orchids are tropical plants that originated in Asian jungles where high rainfall, humidity and temperatures combine with strong light filtered though the forest canopy result in rapid growth. While our homes do not provide optimum conditions, phalaenopsis will grow adequately well in the same conditions necessary for African violets to thrive.
When buying your moth orchid, look for the freshest blooms with one or more unopened buds remaining at the tip of the spike. If the spike is open to the tip, there is no real way of knowing how long the plant has been in the store. Leaves should be glossy and deep green and roots green tipped. However, do not avoid plants that are past their prime, which may be available for a significant discount. Just be prepared to provide extra care.
Individual flowers usually last from one to four months but flower life will be prolonged if the plant is kept away from hot, cold and dry drafts. When the last flower fades, leave the entire spike on the plant. Usually a secondary stalk and a new crop of blooms will develop. When a second stalk develops trim the old stem. Flower spikes usually take 12 to 14 weeks to develop the first flower so be patient. Make sure the flowers are supported.
Your phalaenopsis will grow and flower over a period of many years, if proper conditions are provided. Place in a bright window, water and fertilize regularly and re-pot every year or two (depending on choice of mix). If a sufficiently bright window (east, west or lightly shaded south) is not easily available, supplementary artificial lighting may be provided with the simplest of fluorescent light fixtures.
Water well until the water drains through the drainage holes of the container and then allow the pot to dry until it feels light. Do not allow the pot to sit in standing water.
Fertilizing "weakly weekly" with a balanced fertilizer. If you fertilize every week at one-half to one-quarter strength, you will be able to remember easily: while if you intend to feed only every other week, you may forget whether or not you fed last week.
Re-potting with a fresh, fast-draining but water-retentive medium is essential to a healthy root system. Look for a potting medium that is specifically meant for orchids and soak it before using. Pot when roots are actively growing, evidenced by fresh green root tips, ideally when new root tips are emerging from the base of the plant and when the plant is not flowering. Because these orchids will usually need to be repotted every year or two, select a clean pot that is not too large. Consider the size of the root mass rather than the foliage size. Gently remove the spent material from around the roots and trim any dead or damaged roots. Remember that it is not always possible to get all of the roots into the pot. When a plant is actively growing, it is common to see roots stretching out of the pot. Press firmly, but without excessive pressure, situating the base of the plant at the level of the mix in the pot. Do not water the newly potted plant for a week or two. Humidity is important with the recommended humidity being between 50 and 80 percent. To add humidity, set the plants on trays of gravel, partially filled with water. Be certain that the pots never sit in water. Mist the plants during dry or very warm weather in the morning only. Grouping plants together raises the humidity by keeping the moisture that plants transpire from being lost too quickly.
While it is possible to put plants outside in the warm summer months, be aware that they will be scorched quickly if placed in full sun.