Most people are introduced to orchids through phalaenopsis orchids. These are the thick-leaved plants with elegant, arching sprays of blooms that can be seen in so many design magazines and sitting on coffee tables across America.
There are about 60 true species of phalaenopsis; they are native to tropical Asian countries including the Philippines, Borneo, Java and elsewhere. These plants have been extensively hybridized, and there are thousands of phalaenopsis hybrids, ranging from the stark, classic white hybrid (often called a moth orchid) to jewel-like miniatures with clouds of yellow and candy pink blooms.
Phalaenopsis are low-light orchids and will thrive in an east window, or a shaded southerly or westerly exposure. They do not like direct sunlight and will scorch. They also will do well under common grow lights, positioned about a foot off the plant. A well-grown phal will have darker green leaves on top and streaks of red or burgundy on the undersides.
The phalaenopsis is a monopodial orchid that grows from a single stem. It does not have the large water-storing pseudobulbs found on sympodial orchids, although its leaves can store some water. Thus, the plant has a lower tolerance for drought. During the growth season, water the plant whenever its exposed roots turn silvery white, usually weekly. Try to keep the potting media slightly damp. During the flowering season, you can cut the water back to every other week. The higher the humidity, the more important it is to maintain a good air flow around the roots and leaves.
See Grower's Tips below for watering advice.
During the growing season, fertilize with a weak orchid fertilizer weekly (weakly weekly, as the growers say). Cut fertilizer back to once a month during the winter and flowering season. Some growers like to give the plant a boost of blooming fertilizer in September or October to provoke a flower spike.
Generally, phalaenopsis are considered a warm house plant. During active growth, they like temperatures between about 75 and 85 degrees, but they can adapt to a normal house temperature of 65 to 70 degrees. The higher the temperature, the greater the plant's need for humidity. However, they also like a nice contrast between night and day temperatures. See Blooming below for temperature tips.
Phalaenopsis typically bloom in the late winter or early spring. Their long-lasting flowers are held on arching branches and open successively. A single multi-branching flower spike can have more than 20 flowers. Individual phalaenopsis flowers can last for weeks. To induce a flower spike, the plant needs a few cooler nights, down to 55 degrees. The plants will not bloom well without this temperature contrast.
Potting and Media:
Phalaenopsis can be grown in most orchid potting media, including chunks of pine bark, clay aggregate pellets, charcoal, perlite, sphagnum moss, and styrofoam. They can also be grown in hanging baskets or mounted on slabs in a greenhouse-type environment. As with all epiphytic orchids, they should be planted in free-draining containers. Repot phalaenopsis in spring, after the bloom is done.
Adult phalaenopsis can often go for two years or more before they need to be repotted.
Phalaenopsis are generally very rewarding plants. They are not demanding and, in the right conditions, they will reward the grower with months of showy blooms. It is vitally important, however, that water never be allowed to rest in the growing tip of the plant. This will cause the new leaves to rot, and the plant will die. Thus, they should only be watered in the morning. As with all orchids, the higher the humidity and temperature, the greater the need for turbulent air flow to prevent rot, fungus, and diseases. Successful growth means finding the right balance between humidity, temperature, light and air flow.