The exotic Phalaenopsis orchid (or moth orchid), native only to the tropical regions of Asia and Australia, is most known for brightening up the indoor spaces of home gardeners in the U.S. In fact, this flower is almost impossible to grow outdoors anywhere in continental North America. Still, with several hundred different genera, and thousands of species of orchids to choose from, the Phalaenopsis genus remains the most popular cultivar. It's a particularly good orchid choice for beginner growers. When grown indoors, Phalaenopsis orchids are not temperamental, and under the right conditions, will reward you will showy blooms for months. This thick-leaved, elegant plant is featured in many design magazines for this reason, sitting on coffee tables and desks across America.
|Common Name||Moth orchid, Phalaenopsis, phals|
|Plant Type||Herbaceous flowering perennial, orchid group|
|Mature Size||8 to 36 inches tall (depending on species and variety), 12 inches wide|
|Sun Exposure||Bright shade|
|Soil Type||Moist, bark-like potting media|
|Soil pH||Slightly acidic to neutral|
|Bloom Time||Spring and summer; indoors, it is a repeat seasonal bloomer|
|Flower Color||White, pink, lavender, yellow|
|Hardiness Zones||10 to 12, USDA|
|Native Area||Southeast Asia to the Philippines, New Guinea, and northern Australia|
Phalaenopsis Orchid Care
Phalaenopsis orchids grow on tree trunks and branches in tropical environments. So, when you're growing them as indoor potted plants, it's best to mimic these conditions. Successful growth means finding the right balance between humidity, temperature, light, and airflow.
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.
Phalaenopsis orchids are hardy only in Zones 10 to 12, and you rarely see them growing in the continental United States, other than the southern tip of Florida. Ideal outdoor conditions need to be warm, humid year-round, but not damp or soggy, and the growing location needs to be shady, but bright (no direct sun).
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 experiences some direct light. Rotate your orchid from time to time to keep its growth even. You can also position it under a common grow light, locating the flowers about a foot underneath the light.
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.
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.
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.
Temperature and Humidity
Phalaenopsis is considered a "warm houseplant" and prefers temperatures between 75 and 85 F. Still, they can adapt to normal house temperatures of 65 to 70 F. 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
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.
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 appear on either an old or new flower spike.
Here's how to propagate orchids from a keiki:
- Gather flower scissors, alcohol wipes, a pot, a spray bottle, and an orchid-specific potting medium.
- Wait until the keiki is about a year old, 3 inches long, and has developed two or three leaves of its own and several good roots.
- Disinfect the blades of the scissors with the alcohol wipes and carefully remove the keiki from the parent plant, keeping the roots intact.
- Moisten the bark potting medium and plant the keiki in its own pot (it's okay if the top parts of the roots are exposed).
- Mist the baby plant daily with water until it becomes established.
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 Schiller 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.
- Stuart’s variety 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.
Potting and Repotting
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.
Orchids can also be grown in hanging baskets or mounted on slabs in a greenhouse environment. As with all epiphytic orchids, Phalaenopsis should be planted in free-draining containers and never allowed to sit in water.
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.
Common Pests & Plant Diseases
Phalaenopsis orchids very rarely encounter problems with insects, especially when grown indoors. Still, scale, mealy bugs, slugs, and snails can occasionally move into an outdoor or greenhouse-grown orchid. Most pest conditions can be treated by spraying with insecticidal soap.
As for disease, orchids can sometimes experience fungal conditions such as foliar blights, leaf spots, fungal rots, and flower blights. Most of these conditions can be controlled by removing the affected portion of the plant (leaf, root, or flower) and sometimes treating the plant with a fungicide. Still, all can be prevented by maintaining proper soil conditions.
How to Get Phalaenopsis Orchid to Bloom
In the wild, Phalaenopsis orchids only bloom once a year. Indoors, however, you can get them to bloom every six months with a few simple steps. Once the last bloom has dropped, cut the brown stem off to no more than 3 inches in height. Continue caring for your plant as normal and feeding it a diluted liquid fertilizer to promote growth and blooms. Once the stem has grown a new leaf, it's ready to rebloom. Relocate your orchid to a cooler area—one with temperatures of 55 to 65 F and bright indirect sunlight (possibly outdoors). After one month in this cooler environment, your orchid should produce new blooms.
Common Problems With Phalaenopsis Orchid
Phalaenopsis orchids can suffer from root or stem rot, which usually occurs because the growing medium has been overwatered and is too soggy. Orchids can also experience bud blast—a condition where the flower buds drop without blooming. This is usually caused by sudden changes in temperature, humidity, moisture, or fertilizer. Maintaining ideal growing conditions should lessen the occurrence of problems.
Can you grow Phalaenopsis orchids indoors?
These orchids are often grown as indoor potted plants, where successful growth means finding the right balance between humidity, temperature, light, and airflow. A single multi-branching flower spike can have more than 20 flowers, and individual flowers can last for weeks.
Is it easy to propagate orchids?
Periodically, the plant will naturally produce "baby" orchids known as a keiki. These are identical copies of the parent and normally appear on either an old or new flower spike. After the keiki is about a year old, you can remove it from the parent plant and give it its own pot.
What pests are most common to orchids?
Phalaenopsis orchids have no critical insect or disease problems, but scale, mealy bugs, slugs, and snails are among the pests that occasionally occur.
How do you get an orchid to rebloom?
Light exposure is important. Put it outdoors in shade during the summer, then bring it inside in indirect light in the fall. Cooler fall temperatures can help encourage bud setting. Bring the plant inside when temperatures fall below 50 F.