The graceful stalks of orchids with wide blooms alight on a single curve, like great winged moths. The plants originally came from Southeast Asia, but today you can find "moth orchids" lined up for sale in your supermarket. Phalaenopsis spp., or moth orchid, once a rare acquisition and considered challenging to cultivate, is now an inexpensive indoor potted plant that flowers for up to three months and can be induced to bloom annually for many years. If you've received a plant in full flower, or coaxed your orchid to unfold its creamy wings, following some basic care guidelines helps prolong its flowering period and prepare the plant to bloom again. Although they'll grow in U.S. Department of Agriculture plant hardiness zones 10 through 12, most people use the plants to beautify their homes indoors.
Phalaenopsis are fairly hardy, but they can be slightly fussy when they're ready to flower. Once the spike emerges and shoots up, stake it so the weight of the blooms won't cause the stem to bend perilously. Spikes may take up to eight weeks to mature and should remain in bright but indirect light. Don't turn or move the plant once the buds appear, because the buds are light-seeking and they will twist in the direction of the light and spoil their perfect line of blooms. Keep a blooming plant well watered and wait to move it until three-quarters of the buds are open. After that, it will adjust to relocation, as long as the temperature range is between about 65 degrees Fahrenheit at night and 80 degrees F by day.
Phalaenopsis love to be moist -- the roots should never be permitted to dry out, but they shouldn't sit in water. That means watering about once a week, taking particular care not to splash water on the broad, deep green leaves. Fertilize using a 10-30-20 orchid blend to promote blooming. Mix 1/4 teaspoon of fertilizer into 1 gallon of water and use the solution in place of regular weekly watering. During the growing season, use the mixture for every three waterings and then use regular water for every fourth watering. Using regular water flushes out any salts accumulating in the container. Stop fertilizing during the winter months.
Blooms and Beyond
A Phalaenopsis may be in bloom for up to three months, usually in winter to spring, although some cultivars bloom in summer and some in fall. Once the flowers fade, you may be able to coax another bloom from the old spike, but most types only bloom once per season. Smaller flowers, not as lushly symmetrical, might continue to bloom on the spike but your plant could get sort of weedy-looking. Another option is to cut the spike, leaving at least two nodes. Nodes are the bumpy places where the individual flower stems grew from the spike. A sharp knife, razor, or sterilized cutting tool will do the job -- always use a sterile blade, because orchids are very susceptible to viruses. With any luck, the plant will produce a new spike at a node and erupt into another curve of orchids. If you choose to cut the original stem or spike at the base by the leaves, the plant should send up a new spike and bloom again in a few months. Cutting the spike at the base allows the plant to divert all its energy to establishing strong roots, leading to robust blooms when it's time for the next spike to appear.
Sterilize your pruning tools by wiping the blades off with alcohol and allowing them to dry before using.
If you notice pseudobulbs -- bulbous green shoots -- climbing over the edge of the pot, or if your Phalaenopsis has been happily blooming in the same pot for two years, it's probably time to repot. The new pot should be just a bit larger than the old one -- maybe a finger-width or two wider -- because orchids like snug pots. Consider a clear pot that makes it easier to see when the roots need more water. Phalaenopsis roots like light and they are exposed to more of it in a clear pot. Work the old roots clean of most potting medium gently with your fingers; trim the roots to about 5 inches, and hold the plant at level in the pot as you fill in around it with new potting medium. Tamp the medium down lightly as you go, to hold the orchid in place. Leave the green-tipped roots exposed because they will rot if buried in medium. Water thoroughly and drain until the rootball is just moist. Repotting is best managed when your plant is finished flowering -- often in spring or early summer -- but it may be done at any time of the year.