Moth orchids are great year-round, but they’re especially well-suited for cold days when you’re spending a lot of time indoors. Their elegant flowers will brighten tables and windowsills in your home for months at a time. Don’t be intimidated by their exotic appearance. They need very little to thrive inside.
Kate Santos loves moth orchids. «Dr. Kate,» as her coworkers call her, is the director of research and development for Costa Farms near Miami. It’s the largest grower of indoor plants in the South. «Moth orchids are perfect for new gardeners because they are some of the easiest orchids to grow,» Kate explains. «They also do not require a lot of attention, which makes them great for people who don’t have a lot of extra time.» Even experienced gardeners enjoy these easy flowers, she says, because new variations in flower color, size, and bloom become available each year, so gardeners can add to their existing collections.
| Plant Attributes | |
|---|---|
| Common Name | Moth orchid, Phal |
| Botanical Name | Phalaenopsis spp. |
| Family | Orchidaceae |
| Plant Type | Tender perennial, epiphyte |
| Mature Size | 6-36 in. tall, 8–12 in. wide |
| Sun Exposure | Bright, indirect light |
| Soil Type | Orchid bark mix |
| Soil pH | Slightly acidic (5.5-6.5) |
| Bloom Time | Varies by species |
| Bloom Color | Red, pink, peach, yellow, purple |
| Hardiness Zones | 10–12 (USDA) |
| Native Area | Asia, Australia |
Moth Orchid Care
Moth orchids are epiphytes, which means they grow on the trunks or branches of trees in nature (outdoor conditions aren’t suitable for these plants in the U.S., except on the southern tip of Florida). In the horticultural world, you’ll find them growing in a pot of bark or sphagnum moss.
These plants like humidity, but cannot tolerate being overwatered. For in-depth growing information, visit the American Orchid Society at aos.org. Below, orchid expert Santos offers her best tips for keeping moth orchids happy and blooming.
Light
Orchids like bright, indirect light. An east-facing window is best; western or southern light is fine as long as it’s indirect. North-facing windows generally won’t provide enough light.
Soil
Moth orchids are typically grown in a bark mixture that includes sphagnum moss or other materials to help retain water. Bark alone tends to dry out very quickly without some type of amendment, but at the same time can begin to break down and hold too much moisture in the bottom of the pot. Sometimes plants are sold in pure sphagnum moss, which must be monitored carefully to avoid overwatering.
Water
You’re actually more likely to kill a moth orchid by overwatering than by underwatering. The planting material must be allowed to dry out slightly between waterings, but should not be left dry for extended periods of time. (Bark holds less water than moss, so orchids planted in it should be watered more often.) When the bark or moss is dry to the touch and the pot is light, water your orchid thoroughly until water comes through the drainage hole in the bottom of your pot. This could be once or twice a week for an orchid planted in bark, and less frequently for an orchid planted in moss. Light exposure, seasonal variation, humidity, and planting material all factor into how quickly orchids dry out.
Never leave orchid roots in standing water. Note: Miniature moth orchids, relatively new on the market, are grown in smaller pots and can dry out faster.
Temperature And Humidity
Normal home temperatures are good—about 70 to 80 degrees Fahrenheit in the daytime and above 60 degrees at night. Moth orchids should not be kept at temperatures above 95 degrees or below 55 degrees.
Low humidity can cause orchid leaves to wrinkle. Don’t place your plant in a dry spot such as over a vent or radiator. Misting leaves regularly or placing a wet pebble tray underneath the plant can be used to increase humidity, but don’t allow the pot to sit in standing water.
Fertilizer
Ask your local nursery for an orchid fertilizer, and apply it according to package instructions. Fertilizer is commonly applied twice a month, though some gardeners will dilute fertilizer to 1/4 or 1/2 strength and use it at each watering. For easy feeding, try Dynamite Orchids & Bromeliads (10-10-17) slow-release plant food. Don’t fertilize during winter, when plants are exposed to less light.
Types Of Moth Orchids
You can buy moth orchids just about anywhere—at local nurseries, grocery stores, and big-box retailers. For a great online selection of orchids, including blooming ones you can have mailed as gifts to friends, visit Norman’s Orchids at orchids.com. Also try Carter and Holmes Orchids at carterandholmes.com. Here are a few orchid species you can purchase:
- P. amabilis: Large white flowers; tends to produce two arching spikes at a time
- P. aphrodite: Small white flowers with a reddish interior
- P. bellina: Green flowers with purple interior
- P. equestris: Small purple flowers
- P. fasciata: Small yellow flowers with brownish-red stripes
- P. kunstleri: Star-shaped, waxy yellowish-green flowers with brown mottling
- P. violacea var. coerulea: Fragrant purple or indigo flowers
- P. lueddemanniana: White flowers covered with magenta mottling
- P. micholitzii: Waxy, greenish flowers
- P. schilleriana: Pinkish, fragrant flowers
Propagating Moth Orchids
Moth orchids can produce plantlets called keikis on the flower stem. This tiny plant is a clone of the mother plant. If your orchid grows a keiki, wait until it has developed roots that are 2 or 3 inches long before removing it from the mother plant. Use a sharp, sterile garden knife to cut the keiki from the stem. You can then plant the keiki, following our instructions for potting orchids. Many experts recommend growing the keiki in the same pot as its mother for the first year to help regulate moisture. In another year or two, the younger plant will mature and bloom.
Potting And Repotting Moth Orchids
You may need to repot your orchid every few years, because the growing medium will begin to break down and hold too much moisture. Another reason to repot an orchid is if it outgrows its current pot. Do this when it’s not blooming, as repotting can stress an orchid and cause it to drop its blooms.
Use a container with good drainage holes. Hold the orchid over the container, and fill around its lower roots with commercial orchid bark mix, making certain the plant is sitting on top of the growing medium. Then water the plant.
Common Pests & Plant Diseases
Many orchid problems are due to overwatering or improperly watering. If you find wet-looking patches on the leaves, the plant is likely suffering from a bacterial infection like brown spot or black rot. A bad smell is also an indication of bacteria. Remove affected areas with a sterile blade, and avoid getting the leaves or crown of the plant wet when watering. Spotted leaves without any sign of bad-smelling bacteria or pests can indicate a fungal infection. Again, remove infected areas, and be careful when watering. Spray with a combination bactericide/fungicide.
Mushy or disappearing roots are a sign of root rot from overwatering. Sometimes you may notice wrinkling leaves first—if this symptom is paired with rotting roots, then the problem is overwatering rather than underwatering. Remove infected roots. Consider repotting your plant, especially if the bark in your pot has broken down to the point that it looks like shredded mulch. When you water, make certain to empty out the tray that sits under the pot. Watering early in the day gives the plant more time to dry out by nightfall.
Brown spots on flowers are caused by botrytis blights. Removed the blossoms, make certain you have good air circulation around the plant, and avoid getting water on petals and leaves.
Though your plant may be sheltered from pests indoors, orchids can be infested by scale (insects appear to be circular bumps on stems), mites (tiny spider-like pests that cause stippling on leaves), or mealybugs (white, fluffy insects). Spray the plant with neem oil or insecticidal soap.
How To Get Moth Orchids To Bloom
Orchids are often flowering already when you purchase them from the store. Once an orchid has stopped flowering, you can cut off the bloom spike at the base of the plant. Keep fertilizing. Leave the pot in bright, indirect light. Your orchid should rebloom within a year.
If your orchid doesn’t rebloom, you can encourage the plant by moving it to or near a brighter window. Another trick is to allow temperatures to drop at night for a period.
These orchids will sometimes develop new flower beds on an existing spike after flowers have faded. If you see a bud developing, cut the spike about 1/2 inch above it, and a new flower will grow.
Common Problems With Moth Orchids
Flopping
Underwatering can cause moth orchids to flop and one or more leaves to turn yellow. Although the leaves are succulent, moth orchids can’t go without water for weeks. Resume a regular watering schedule and the orchid will slowly recover.
Yellow Leaves
Orchids do naturally lose their leaves from time to time, so it’s not always a reason to panic, especially if you see a new leaf or flower spike appearing. Yellow leaves can be related many other factors, so you’ll need to consider weather, water, and sun exposure to determine what is causing the problem. Scorched leaf tips and yellowing are good indications your plant is getting too much direct sunlight. If your plant has been exposed to temperatures colder than 60 or hotter than 80, this may cause yellowing. Excessive fertilizing, no fertilizing, and overwatering are other common causes.