If you're looking for a great houseplant for winter gift-gifting, the moth orchid (Phalaenopsis) is hard to beat. No other orchid is easier to grow indoors, and it makes a vibrant, long-lasting display. Moth orchids grow well on a windowsill, in a bright room, or under artificial lights.
Each arching flower spray laden with up to a dozen or more blooms lasts one to four months, sometimes longer. Best of all, moth orchids reach peak bloom during the year's gloomiest days, from December to March. You can even extend the bloom season into early summer by adding a few later-blooming hybrids to your collection. Look for crosses between phalaenopsis and doritaenopsis. They are just as easy to grow.
Moth orchids today are more widely available and less expensive than they were just a few years ago. A budded orchid in a five-inch pot typically costs $25 to $35, about 30 percent less than it did five years ago. Properly cared for, orchid plants live for many years.
Light. Moth orchids grow well in a bright window with indirect light. An east window is usually ideal. A south or west window will also work if you provide some shade such as a sheer curtain. In cloudy northern regions, a full southern exposure may be necessary during winter. As a guideline, lay a piece of white paper in the proposed plant location and raise your hand, palm down, about a foot above it. If your hand casts a well-defined shadow, the light is too bright. If there is no shadow at all, the light is too dim. A fuzzy shadow indicates that the light is just right.
Artificial lighting is an option that makes sense in many situations. Place four 4-foot fluorescent tubes in a single fixture (or in two shoplight fixtures hung side by side). Alternate "cool" with "warm" lights, or alternate cool lights with wide-spectrum lights designed for plant growth.
Position the lights 6 to 12 inches above the leaves. Turn the lights on 12 to 16 hours during the day. Moth orchids grow well under the lights, but once blooming you'll want to move them to a location where they are easier to see and appreciate.
Read the Leaves. Pay attention to the foliage of your orchid to learn if the light you are providing is right. If new leaves are lush, soft, and darker in color than the mature leaves, the orchid is not getting enough light. Plants won't flower if the light is too low. Foliage that is stunted, hard, and yellow indicates that the light is too bright.
Temperature. Provide orchids with night temperatures ranging from 60 degrees F. to 65 degrees F. and day temps of 70 degrees F. to 95 degrees F. Plants grow faster in higher temperatures, but they also need more humidity and air movement when it's hot. To initiate flower spikes, provide nighttime temperatures to 55 degrees F. for several weeks in fall. Avoid exposing plants to fluctuating temperatures as the buds develop or the buds may drop just as they are ready to open.
Ventilation. Good ventilation is essential. Air movement around your orchid helps to prevent diseases. Good cross-ventilation is usually sufficient, but keep plants away from drafty, cold windows.
Water. Don't allow bark around moth orchid roots to dry completely. Nor should the plant's roots stand in water. Overwatering will rot the roots, causing the orchid to die. Depending on your climate and the season, frequency of watering may range from every other day to every 10 days. When you do water your orchid, flush the growing medium with water until excess runs out the drainage hole. The best time to water is morning so that leaves are dry by nightfall, making them less prone to disease. Use a cotton swab to daub up any water left standing at the base of the leaves.
Humidity. Moth orchids prefer humidity between 50 and 80 percent. To increase humidity, fill a plastic or glass tray with gravel or pebbles and partially fill the tray with water. Place the orchid on the gravel or stones; the bottom of the pot should not touch the water. In very dry situations, mist plants in the morning; allow leaves to dry off by night.
Fertilizing. Fertilize moth orchids year-round. When weather is warm, apply a balanced fertilizer, such as 20-20-20, twice a month. In cooler, lower light situations, apply fertilizer once a month.
Potting and Repotting. Use a medium-size fir bark (1/2 to 5/8) for moth orchids. Repot when the bark starts to decompose, about every two years. The best time to repot is in spring, after blooming, when the orchid is developing new roots.
The nonprofit American Orchid Society offers a wealth of information about orchids. For the $36 annual membership, you receive the monthly AOS Bulletin.
Write to the orchid society at The American Orchid Society, 16700 AOS Lane, Delray Beach, FL 33446-4351, or call (561) 404-2000. Visit the AOS Web site at www.orchidweb.org.
A free lance writer, Lynn Ocone grows dozens of phalaenopsis orchids in her Burlington, Vermont home.
Article published on June 23, 2008.