The Nun Orchid (Phaius tankervilleae) is a captivating terrestrial orchid known for its striking appearance and relatively straightforward care. Its common name comes from the hooded shape of its blossoms, which resemble a nun’s veil. This orchid features large, pleated leaves and tall flower stalks, up to four feet, displaying vibrant flowers in shades of white, brown, mauve, and yellow. Native to tropical and subtropical regions of Asia and the Pacific Islands, Phaius tankervilleae is suitable for both indoor and garden settings in appropriate climates.
Basic Nun Orchid Care
Nun Orchids thrive with consistent attention to their environmental needs. Understanding these basic requirements ensures robust growth and flowering.
Light Requirements
Nun Orchids prosper in bright, indirect light, mimicking their natural habitat beneath tree canopies. Direct, intense sunlight, especially during the hottest parts of the day, can lead to leaf burn and stress. Yellow or scorched leaves indicate excessive light exposure. Insufficient light can result in yellowing leaves and a lack of blooms, requiring the plant to be moved to a brighter location.
Watering Techniques
Consistent moisture is important for Nun Orchids, reflecting their preference for humid, moisture-rich environments. The soil should remain evenly moist, but not waterlogged, as this can lead to root rot. Allow the top two inches of the potting medium to dry out slightly between waterings before rehydrating. Watering in the morning is beneficial, allowing foliage to dry before cooler evening temperatures, which helps prevent fungal issues.
Humidity and Temperature
Nun Orchids flourish in moderate to high humidity, ideally around 50-80%. In drier indoor environments, humidity can be augmented by placing the pot on a pebble tray filled with water or by using a cool-mist humidifier. Average room temperatures between 65-75°F (18-24°C) are suitable during the day. A slight temperature drop at night, typically 10-15°F cooler, can encourage blooming.
Potting Medium
A well-draining yet moisture-retentive potting mix is ideal for Nun Orchids. A suitable blend includes a commercial terrestrial orchid potting mix with added components like fir bark, sphagnum moss, perlite, or pumice to enhance aeration and drainage. Incorporating peat moss, compost, or decomposed pine bark can also provide the organic matter these orchids prefer. The chosen medium should prevent waterlogging while retaining adequate moisture for the roots.
Fertilizing
During active growth, from spring through fall, Nun Orchids benefit from regular fertilization. A balanced, water-soluble fertilizer, such as a 20-20-20 formula, applied at half or quarter strength every two to four weeks is recommended. High-phosphorus fertilizers can also promote root development and vibrant blooms. Reduce or cease fertilization during the winter resting period.
Repotting Nun Orchids
Repotting Nun Orchids is necessary every two to three years, or when the plant becomes root-bound or the potting medium degrades. The best time for repotting is after the flowering period, allowing the plant to recover and establish new growth. Choose a new pot slightly larger than the previous one, ensuring adequate drainage holes. A pot height approximately 2.5 cm taller than the pseudobulb is sufficient. Gently remove the orchid, inspect roots, and remove any dead material before placing it into fresh potting mix.
Encouraging Blooms and Maintenance
Specific care practices encourage a Nun Orchid to produce impressive blooms. Providing a cool resting period during winter, with night temperatures dropping to 55-60°F (13-16°C), helps initiate flower spike development. Bright, indirect light year-round is also important for blooming, as insufficient light prevents flower formation. After flowers fade, trim spent flower spikes at their base to promote new growth. Regularly remove yellowing or damaged leaves to maintain appearance and direct energy towards healthy foliage and future blooms.
Common Problems and Solutions
Nun Orchid owners may encounter common issues affecting plant health and flowering. Yellowing leaves often signal improper watering (overwatering leading to root rot or underwatering causing dehydration) or nutrient deficiencies. Adjust watering frequency to allow topsoil to dry slightly, and use a balanced fertilizer if needed. A lack of blooms is often due to insufficient light, inadequate temperature fluctuations, or a missed winter resting period; ensure a brighter location and cool night-time temperatures. Stunted growth may indicate a need for repotting due to degraded potting medium or nutrient lack.
Pest and Disease Management
Nun Orchids are resilient, but can be affected by common pests and diseases. Mealybugs and spider mites are sap-sucking insects that infest the plant, leading to stunted growth and yellowing leaves. For minor infestations, manually remove pests with rubbing alcohol on a cotton swab or rinse with water; use insecticidal soap or neem oil for widespread issues. Root rot, a common disease, results from overwatering and poor drainage, causing mushy, dark roots; improve drainage and allow soil to dry between waterings to prevent this. Fungal spots on leaves occur from excessive humidity or water remaining on foliage; ensure good air circulation and avoid overhead watering.