How To Grow And Care For Moth Orchids


Updated: 25 Oct, 2023

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Phalaenopsis orchids, indigenous solely to the lush tropical landscapes of Asia and Australia, have become synonymous with brightening up the interiors of American homes. Their exotic allure renders them nearly impractical to cultivate outdoors anywhere in mainland North America. Amidst the myriad of orchid varieties, the Phalaenopsis genus stands as the most favored, especially among novices in orchid cultivation.

Emerging from leaf joints or axils, the flower stalks of these orchids frequently bear numerous flower buds, promising a month-long or even lengthier bloom with proper attention. These enduring blossoms grace gracefully arched branches, unfurling in succession. A solitary, multi-branched flower spike may boast over 20 flowers, each with a remarkable longevity measured in weeks.

Read also: Understanding Natural Light for Houseplants

Plant Attributes
Common NameMoth orchid, Phal
Botanical NamePhalaenopsis spp.
FamilyOrchidaceae
Plant TypeTender perennial, epiphyte
Mature Size6-36 in. tall, 8–12 in. wide
Sun ExposureBright, indirect light
Soil TypeOrchid bark mix
Soil pHSlightly acidic (5.5-6.5)
Bloom TimeVaries by species
Bloom ColorRed, pink, peach, yellow, purple
Hardiness Zones10–12 (USDA)
Native AreaAsia, Australia

What are Moth Orchids?

Moth Orchids, scientifically known as Phalaenopsis, are a popular and diverse genus of orchids characterized by their elegant, butterfly-like blossoms. They are renowned for their graceful, arching stems and large, flat, often vividly colored flowers. Native to the tropical regions of Asia, including countries like Indonesia, Malaysia, the Philippines, and parts of Australia, Moth Orchids have become one of the most widely cultivated orchid varieties worldwide.

They are favored for their relatively easy care compared to some other orchid species, making them a popular choice among both beginners and experienced orchid enthusiasts. Moth Orchids come in a wide range of colors and patterns, making them a versatile and beautiful addition to indoor gardens and floral displays.

Can You Grow Phalaenopsis Orchids Inside?

Phalaenopsis orchids thrive exclusively in the balmy embrace of USDA zones 10 to 12, making sightings of them in the open air a rare treat in the continental United States, primarily limited to the southernmost tip of Florida. Virtually everywhere else, cultivating them indoors is the sole means of replicating the precise growing conditions these orchids demand.

How to Grow Phalaenopsis Orchids Indoors

When cultivated indoors under optimal conditions, Phalaenopsis orchids prove to be undemanding, generously gracing you with vibrant displays of blooms that can last for months. Naturally found on tree trunks and branches in tropical climes, it’s advisable to replicate these surroundings for best results. Achieving flourishing growth hinges on striking the perfect equilibrium between humidity, temperature, light, and airflow.

Sunlight:
Proper lighting is essential for Phalaenopsis growth, though direct sunlight can harm the leaves. In winter, consider placing the orchid near a south-facing or east-facing window that receives indirect light. Regularly rotate the orchid to ensure even growth. Adequate lighting will result in light green leaves. Too little light leads to darker green leaves, while excessive light may cause a pink or reddish tint along the leaf edges, eventually turning yellow.

Artificial Light:
If natural light is insufficient, consider using supplemental grow lights. Opt for fluorescent tubes (either 40 or 74 watts, depending on length) and position the Phalaenopsis about 12 inches below the light source.

Temperature and Humidity:
Phalaenopsis thrives as a “warm houseplant” and favors temperatures between 75 and 85 degrees Fahrenheit. However, they can adapt to standard indoor temperatures of 65 to 70 degrees Fahrenheit. Higher temperatures necessitate increased humidity levels, along with enhanced airflow to prevent rot, fungi, and disease. Many successful orchid growers maintain a constant ceiling or stationary fan in their growing spaces.

Orchids also benefit from fluctuating day and night temperatures. To encourage flowering, the plant requires a few cooler nights, with temperatures around 55 degrees Fahrenheit.

Watering:
As a “monopodial” orchid, Phalaenopsis lacks the water-storing pseudobulbs found in branching orchids, making it less drought-tolerant. Throughout the growing season, water the plant weekly or whenever its exposed roots turn silvery white (approximately once a week). Run warm water over the plant, bark, and aerial roots for about 10 minutes, allowing ample time for absorption. Ensure thorough drainage before returning it to its window, avoiding any water accumulation around the stem.

This can lead to rotting of new leaves and eventual plant demise. Once watered, roots should transition from silver to pale green. During the flowering season, reduce watering to every other week. Be cautious of overwatering, which can lead to root or stem rot due to excessively soggy growing medium.

Fertilizer:
In the growing season (summer), apply diluted orchid fertilizer every three to four weeks. Skip feedings during fall, winter, and spring (flowering season) to avoid excessive foliage growth at the expense of blooms. Some growers opt for a “bloom booster” in September or October to stimulate flower spike production.

Pruning and Maintenance:
Trim mature orchids once a year during their dormancy period, after blooms have faded. Using clean scissors or a knife, trim the top of the stem about one inch above a node to encourage new stem growth and more blooms. Carefully deadhead spent flowers, though they may naturally fall off. Remove any brown or black leaves, and trim back unhealthy roots that appear dead and brown or are mushy. It’s normal for Phalaenopsis to grow roots above the soil — these are aerial roots and should be left untouched.

Types of Phalaenopsis Orchids

There are approximately 60 distinct species of Phalaenopsis orchids. Through extensive hybridization, thousands of hybrids have emerged, ranging from the timeless white moth orchid to petite, jewel-toned varieties boasting clouds of yellow and candy-pink blossoms. Some cherished cultivars include:

  • Phalaenopsis ‘Liodoro’: This variety showcases undulating, vibrant green leaves and star-shaped flowers in shades of pink and purple. It can grow to a height of up to 19 inches.
  • Phalaenopsis schilleriana: Adorned with large, 2.5-inch pink and purple blooms, this orchid features variegated dark green leaves. Each stem of this variety can bear an impressive 200 flowers.
  • Phalaenopsis stuartiana: Distinguished by its white flowers adorned with yellow and red dots on multiple branches, this orchid can reach heights of up to 30 inches.
  • MiniPhalaenopsis: These diminutive orchids require less water due to their smaller size and come in an array of flower colors.

Container and Size

Like all epiphytic orchids, Phalaenopsis should be potted in containers with ample drainage, featuring sizable drainage holes to prevent waterlogging.

Typically, Phalaenopsis thrive in 4- or 6-inch azalea pots, and it’s rare to find them in pots larger than 6 inches in diameter. Whether plastic or terra cotta, both types of pots are suitable as long as they facilitate excellent drainage.

Potting Soil and Drainage

In their natural habitat, moth orchids are typically found growing on trees. This categorizes them as epiphytes, a type of plant that relies on a host but is not parasitic. To replicate these conditions, potted orchids are commonly cultivated in a potting mixture composed of fir tree bark, redwood bark chips, or Monterey pine bark chips.

Most bark-based potting mediums, enriched with perlite, sphagnum moss, charcoal, or coconut husk chips, aid in water retention for the orchid. Alternatively, you can opt for a commercial potting mix specifically designed for orchids. It’s crucial to ensure ample air circulation around the root system of Phalaenopsis, as they do not thrive in a suffocating substrate.

Potting and Repotting Phalaenopsis Orchids

In the spring, when the bloom cycle concludes and you observe roots protruding from the pot, it’s time to repot your Phalaenopsis orchids. Typically, mature Phalaenopsis can go for about two years before requiring repotting. Select a pot that is one to two inches larger than the current one and sterilize it with a diluted bleach solution (as orchids are highly sensitive to bacteria).

Thoroughly wash your hands and any tools you’ll be using. Allow the pot to air-dry completely, then fill it with an orchid-specific potting mix. Gently extract the orchid from its current pot, trimming away any discolored or dead roots. Place it into the new pot, nestled in the moistened bark medium. Gently pack the substrate around the roots. Mist the orchid daily until new roots start to emerge.

Propagating

Orchids can be propagated through seeds, but this process is intricate and time-consuming, requiring specialized laboratory equipment. As such, it’s typically best left to commercial growers. However, for home cultivators, propagating a moth orchid can be achieved by replanting the naturally occurring “baby,” known as a Keiki. Keikis are essentially identical replicas of the parent plant and can emerge on both old and new flower spikes. Once the Keiki reaches about a year in age, measures around 3 inches in length, and has developed two or three leaves along with robust roots, it’s ready for separation from the parent plant and can be potted independently.

Here’s a step-by-step guide on propagating orchids from a Keiki:

  • Gather flower scissors, alcohol wipes, a suitable pot, a spray bottle, and an orchid-specific potting medium.
  • Wait until the keiki is approximately a year old, has reached a length of about 3 inches, and exhibits two or three leaves of its own, along with well-developed roots.
  • Sterilize the scissor blades using alcohol wipes, and delicately detach the keiki from the parent plant, taking care to preserve the integrity of the roots.
  • Dampen the bark-based potting medium and plant the keiki in its designated pot. It’s acceptable if the upper portions of the roots are exposed.
  • Mist the young plant daily with water until it establishes itself and takes root.

Common Pests & Plant Diseases

Many orchid issues stem from improper watering, particularly overwatering. If you notice moisture-laden patches on the leaves, it’s likely due to a bacterial infection such as brown spot or black rot. An unpleasant odor can also signal bacterial presence. To address this, use a sterile blade to remove affected areas and take care to keep the leaves and crown dry when watering. If you observe spotted leaves without signs of bacterial infection or pests, it may indicate a fungal issue. Again, carefully trim away infected areas and consider using a combination bactericide/fungicide spray.

Mushy or disappearing roots are indicative of root rot, often caused by excessive watering. Sometimes, wrinkled leaves may precede this symptom. If you see both signs, overwatering is likely the problem rather than underwatering. Remove affected roots and consider repotting, especially if the bark in the pot has deteriorated to a mulch-like texture. When watering, be sure to empty the tray beneath the pot. Watering earlier in the day allows the plant more time to dry out by nightfall.

If you observe brown spots on the flowers, it may be due to botrytis blights. Remove the affected blossoms, ensure good air circulation around the plant, and take care to avoid water contact with petals and leaves.

Even if your orchid is indoors, it’s not entirely immune to pests. Keep an eye out for scale (roundish bumps on stems), mites (tiny spider-like pests causing stippling on leaves), or mealybugs (white, fluffy insects). Combat these with neem oil or insecticidal soap spray.

How To Get Moth Orchids To Bloom

Orchids are often already in bloom when purchased, and once they cease flowering, you can trim the bloom spike at the base of the plant. Continue with regular fertilizing and ensure the pot remains in bright, indirect light. With these conditions, your orchid should undergo a new flowering cycle within a year.

If your orchid doesn’t rebloom, consider relocating it to a brighter window or providing occasional drops in nighttime temperatures for a period.

Sometimes, these orchids will generate new flower buds on an existing spike even after the initial flowers have faded. If you observe a budding, trim the spike about 1/2 inch above it, and a fresh blossom will emerge.

Common Problems With Moth Orchids

Flopping:

If you notice your moth orchid drooping and some leaves turning yellow, it’s likely a sign of underwatering. Despite their succulent nature, moth orchids still need regular watering and can’t go without it for extended periods. Get back on a consistent watering schedule, and the orchid should gradually recover.

Yellow Leaves:

While it’s natural for orchids to shed leaves occasionally, seeing a new leaf or flower spike emerge is a reassuring sign. Yellowing leaves can be attributed to various factors, so consider elements like weather conditions, watering habits, and sun exposure to pinpoint the issue. If you notice scorched leaf tips and overall yellowing, it’s an indication that your plant is receiving too much direct sunlight. Exposure to temperatures below 60 or above 80 degrees Fahrenheit can also lead to yellowing. Over-fertilizing, lack of fertilizing, and overwatering are other common culprits for yellowing leaves.

Where are Moth Orchids Native to?

Moth Orchids are native to the tropical regions of Asia, including countries like Indonesia, Malaysia, the Philippines, and parts of Australia.

How Should I Water My Moth Orchid?

It’s best to water Moth Orchids thoroughly but allow the top layer of the potting medium to dry out before the next watering. Be cautious of overwatering, as they’re sensitive to waterlogged conditions.

What Kind of Light Do Moth Orchids Need?

Moth Orchids thrive in bright, indirect light. They should be shielded from direct sunlight, which can scorch their leaves.

How Do I Repot a Moth Orchid?

Repot Moth Orchids in spring when their bloom cycle is finished and roots are visible outside the pot. Use a pot slightly larger than the current one, with proper drainage. Be sure to disinfect tools and handle roots with care.

Why Are My Moth Orchid’s Leaves Turning Yellow?

Yellowing leaves may indicate various issues, such as overwatering, inadequate light, or nutrient deficiencies. Assess watering habits, and light exposure, and consider adjusting their environment accordingly.

How Can I Encourage Blooming in My Moth Orchid?

Moth Orchids typically bloom when they experience a temperature drop at night. Provide a contrast between day and night temperatures to stimulate flower spikes.

What Can I Do About Pests on My Moth Orchid?

Keep an eye out for common pests like scale, mites, or mealybugs. Use natural remedies like neem oil or insecticidal soap to combat infestations.

Conclusion

Moth Orchids, scientifically known as Phalaenopsis, are a captivating genus of orchids renowned for their exquisite, butterfly-like blossoms. Native to the tropical regions of Asia and Australia, they have become a cherished addition to indoor gardens worldwide. With their graceful arching stems and vibrant, flat flowers, Moth Orchids bring a touch of natural elegance to any space.

Their popularity stems not only from their breathtaking beauty but also from their relatively manageable care requirements, making them accessible to both novice and seasoned orchid enthusiasts. With a diverse range of colors and patterns, Moth Orchids offer a versatile and stunning option for floral arrangements and indoor horticulture. Embodying both grace and resilience, these orchids continue to captivate the hearts of plant lovers and add a touch of nature’s artistry to our lives.


Mary Lloyster

Mary Lloyster

Mary, the ultimate oracle of indoor gardening! With years of experience and a flourishing indoor expo, Mary has become our go-to expert for all things related to house plants and indoor gardening. Despite her background in Political Science, Mary has discovered a delightful way to blend her full-time job with a touch of relaxation through indoor gardening. Now, she eagerly shares her wisdom and experiences with our readers on a daily basis. If you have any inquiries about house plants, indoor gardening techniques, or caring tips, don't hesitate to leave a comment for Mary in the designated section below!

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