The “moon orchid” is a popular houseplant known for its long-lasting flowers. This common name refers specifically to Phalaenopsis orchids, a genus recognized for its relatively easy care compared to many other orchid varieties. Their blooms can persist for several months. Phalaenopsis amabilis is a notable species often called the moon orchid. These orchids are epiphytic in their natural habitat, meaning they grow on other plants like trees, rather than in soil.
Moon Orchid Care
Light Needs
Moon orchids thrive in bright, indirect light. An east-facing window is often ideal, providing gentle morning sun, while a shaded south or west-facing window can also work. Too much direct sunlight can scorch their leaves, causing them to turn yellow or bleach white. Conversely, insufficient light can lead to dark green, stiff leaves and inhibit blooming. The ideal leaf color for a well-lit orchid is a light to medium green, sometimes with a hint of red at the base.
Watering Practices
Moon orchids do not tolerate constantly wet roots. The “soak and dry” approach involves submerging the pot in water for 15-30 minutes, allowing the medium to absorb moisture before draining completely. Watering frequency depends on the potting medium and environmental conditions, typically once a week or every two weeks when the medium feels dry. Orchid roots provide a visual cue: they appear silvery or grayish-white when dry and turn green when wet. Avoid letting water sit in the crown (the center where leaves emerge), as this can lead to crown rot.
Humidity and Temperature
Moon orchids prefer warm and humid conditions. Ideal daytime temperatures are 70-80°F (21-27°C), with nighttime temperatures around 60-65°F (16-18°C). Maintain a humidity level of 50-70%. To increase humidity, place the orchid on a pebble tray filled with water (ensuring the pot does not sit directly in the water) or use a room humidifier. Avoid placing orchids near drafts from open windows, fans, or air conditioning vents, as this can cause stress.
Potting and Medium
Moon orchids require a specialized potting medium that provides excellent drainage and aeration, with common components including fir bark, sphagnum moss, charcoal, and perlite. Fir bark promotes good airflow and drainage, while sphagnum moss helps retain moisture. Repotting is needed every one to two years, or when the potting medium starts to break down and decompose, indicated by a sour odor or compaction. Signs that an orchid needs repotting also include roots becoming too crowded or growing out of the pot’s drainage holes. When repotting, remove old, degraded medium and trim any dead, mushy, or shriveled roots before placing the plant in a slightly larger pot with fresh mix.
Fertilization
Moon orchids require regular, but dilute, fertilization during active growth periods. Use an orchid-specific fertilizer, such as a balanced formula like 20-20-20 or one designed for blooming. Dilute the fertilizer to one-quarter or one-half strength of the manufacturer’s recommendation. Fertilize every two to four weeks during active growth, and less frequently or pause during dormancy or winter. Always water the orchid before fertilizing to prevent root burn from concentrated salts. Regularly flushing the pot with plain water helps prevent fertilizer salt buildup in the medium.
Encouraging Reblooming
Encouraging a moon orchid to rebloom involves providing specific environmental triggers after its initial flowering. A key factor is a slight drop in nighttime temperatures to around 55-65°F (13-18°C) for several weeks. This cooler period signals the plant to initiate new flower spikes. Maintain bright, indirect light during this phase to support the plant’s energy production.
After the last bloom fades, cut back the old flower spike. If the spike is still green, cut it about half an inch above a node (a small bump on the stem) to potentially encourage a new side branch. If the spike turns brown and dries, cut it back close to the plant’s base. New flower spikes are smooth and pointed, distinguishing them from new root growth, which is rounded at the tip. Continue regular care, including appropriate watering and fertilization, to support the plant’s energy reserves for reblooming.
Addressing Common Moon Orchid Issues
Common issues can arise when caring for moon orchids. Yellowing leaves can result from overwatering (leading to root rot), underwatering (dehydration), too much direct light, or nutrient deficiencies. Check roots for signs of rot (mushy, brown) or dehydration (shriveled, silvery) to diagnose watering issues. If leaves yellow from too much light, move the plant to a shadier location.
Shriveled roots indicate underwatering or root rot preventing water absorption. Adjust the watering schedule to ensure the medium dries slightly between waterings, but not completely. A lack of blooms is due to insufficient light or the absence of cool night temperatures to trigger flowering.
Moon orchids are susceptible to common houseplant pests like mealybugs, scale insects, aphids, and spider mites. Mealybugs appear as white, cottony masses; scale insects are small, immobile bumps on stems and leaves. Aphids are tiny, soft-bodied insects often found on new growth; spider mites create fine webbing and cause stippling on leaves. Isolate an infested plant and treat with methods like wiping pests with rubbing alcohol or using insecticidal soap to manage these issues.