The flower stalks of these orchids grow from leaf joints, or axils, and often bear multiple flower buds, which can bloom for a month or more when properly cared for. Their long-lasting flowers are held on arching branches and open successively. A single multi-branching flower spike can have more than 20 flowers, and individual flowers can last for weeks.
How to Grow Phalaenopsis Orchids Indoors
Phalaenopsis orchids are not temperamental when grown indoors and under the right conditions, they will reward you with showy blooms for months. These orchids grow on tree trunks and branches in tropical environments. So it’s best to mimic these conditions. Successful growth means finding the right balance between humidity, temperature, light, and airflow.
Sunlight
Good lighting is required to grow Phalaenopsis, but direct sunlight will scorch the leaves. During the winter, however, you can place the orchid in a south-facing or east-facing window that gets some direct light. Rotate your orchid from time to time to keep its growth even. A plant with proper lighting will produce light green leaves. Too little light will result in dark green leaves, and too much light will cause a pink or reddish tinge to develop along leaf margins, which will eventually turn yellow.
Artificial Light
If there is not sufficient natural light, you can also position the plant under supplemental grow lights. The lights of choice for orchids are fluorescent tubes (40 or 74 watts depending on length), and locate the Phalaenopsis 12 inches underneath the light.
Temperature and Humidity
Phalaenopsis is considered a “warm houseplant” and prefers temperatures between 75 and 85 degrees Fahrenheit. Still, they can adapt to normal house temperatures of 65 to 70 degrees Fahrenheit. The higher the temperature, the greater the plant’s need for humidity, and the higher the humidity and temperature, the greater the need for turbulent airflow to prevent rot, fungus, and disease. Many successful orchid growers run a ceiling fan or stationary fan constantly in rooms where they grow orchids. Orchids also like contrasting night and day temperatures. To induce a flower spike, the plant needs a few cooler nights, with temperatures around 55 F, in order to bloom.
Watering
Phalaenopsis is a “monopodial” orchid, which means that it grows from a single stem. It does not have the large water-storing pseudobulbs found on sympodial (or branching) orchids, hence, this plant has a lower tolerance for drought. During the growing season, water the plant weekly or whenever its exposed roots turn silvery white (about once a week). Run warm water over the plant, bark, and aerial roots three or four times over the course of about 10 minutes, giving the orchid plenty of time for absorption. Then, make sure it’s completely drained before you return it back to its window. Water should never be allowed to rest around the stem of the plant. This will cause the new leaves to rot, and the plant will die. Once the roots have been watered, they should turn from silver to pale green. During the flowering season, you can cut the waterings back to every other week. Phalaenopsis orchids can suffer from root or stem rot, which usually occurs because the growing medium has been overwatered and is too soggy.
Fertilizer
During the growing season (summer), fertilize your orchid with a diluted orchid fertilizer every third or fourth week. Skip feedings during fall, winter, and spring (flowering season), as too much fertilizer will lead to excessive foliage and no blooms. Some growers like to give the plant a “bloom booster” in September or October to provoke a flower spike.
Pruning and Maintenance
Prune mature orchids once a year during their dormancy period, after the blooms have faded. Using clean scissors or a knife, cut the top portion of the stem back to one inch above a node to encourage a new stem section and more blooms. You can also carefully deadhead the plant, however, spent flowers may just fall on their own. Remove any brown or black leaves, and snip back unhealthy roots that are either dead and brown, or mushy. It is normal for your orchid to grow roots above the soil. These are aerial roots—don’t cut them off. You can just leave them.
Types of Phalaenopsis Orchids
There are about 60 true species of Phalaenopsis orchids. These plants have been extensively hybridized, and there are thousands of hybrids, ranging from the classic white hybrid moth orchid to jewel-like miniatures, with clouds of yellow and candy pink blooms. Some grower favorites include:
Phalaenopsis ‘Liodoro’ produces wavy, bright green leaves and pink and purple star-like flowers. This plant can reach a height of 19 inches.Phalaenopsis schilleriana boasts large 2.5-inch, pink and purple flowers, with dark green variegated leaves. Each stem on this variety can grow up to 200 flowers.Phalaenopsis stuartiana produces white flowers with yellow and red dots on multiple branches, and can reach up to 30 inches high.Mini Phalaenopsis require less water due to their smaller stature and come in an assortment of flower colors.
Container and Size
As with all epiphytic orchids, Phalaenopsis should be planted in free-draining containers with large drainage holes so they never sit in water. Most Phalaenopsis fit in a 4- or 6-inch azalea pot, and they are usually never planted a pot larger than 6 inches in diameter. As long as the pot as excellent drainage, both plastic as well as terra cotta pots are fine.
Potting Soil and Drainage
In native conditions, moth orchids grow on trees. For this reason, they are considered an epiphyte—a type of plant that requires a host, but is not parasitic. To mimic these conditions, potted orchids are often grown in a potting mix made from fir tree bark, redwood bark chips, or Monterey pine bark chips. Most bark potting media, complete with perlite, sphagnum moss, charcoal, or coconut husk chips will help the orchid retain water. You can also buy a commercial potting mix that is made especially for orchids. Phalaenopsis need plenty of air circulation around their root system, as they don’t thrive in a suffocating medium.
Potting and Repotting Phalaenopsis Orchids
Repot Phalaenopsis orchids in the spring, after the bloom is done and when you see roots growing out of the pot. Adult Phalaenopsis can often grow for two years before they need to be repotted. Use a pot that is an inch or two bigger than the existing pot, and disinfect it with a weak bleach solution (orchids are very sensitive to bacteria). Wash your hands and any tools you’ll be using thoroughly. Let the pot dry fully, and then fill it with an orchid potting media. Gently remove the orchid from its existing pot, cut away any brown roots, and then place it into the new pot with the moistened bark medium. Gently push the soil around the roots. Mist daily until new roots form.
Propagating
Orchids can be propagated by seed, but the process is time-consuming and requires special laboratory equipment, so it’s best to leave this to commercial growers. Home growers, however, can propagate their moth orchid by replanting the orchid’s naturally produced “baby,” known as a keiki. Keikis are identical copies of the parent that periodically appear on either an old or new flower spikes. After the keiki is about a year old, you can remove it from the parent plant and give it its own pot. Here’s how to propagate orchids from a keiki:
