Culture
Grow in an organically rich, well-drained, terrestrial orchid culture medium. Keep plants consistently moist, but avoid excess moisture which may lead to root problems including rots. Plants prefer intermediate to warm temperatures in the range of 60–70°F, with bright light to light shade, but not direct sun. Humidity should be 50% or greater. Plants perform best with regular fertilization. Fertilize weekly at half strength after a thorough watering. Water early in the day, but avoid wetting the leaves. Flush the growth medium often to avoid salt buildup. Watering with distilled water prevents the leaf tips from turning brown. Good air circulation helps prevent fungal problems. Tall flower spikes require staking. Repot after flowering, splitting growth into four pseudobulbs per pot. Propagate from flower stalks by cutting each stalk into pieces after bloom, one “eye” per piece, and laying the pieces on damp sphagnum moss to form plantlets.
Noteworthy Characteristics
Phaius is a genus of around 40 species of terrestrial orchids native to tropical Africa,tropical and subtropical Asia, and Oceania. Phaius tancarvilleae (the nun’s orchid) is the species most often found in commerce. These are attractive, large plants. They have rounded fleshy pseudobulbs (stems) and large, pleated, broad leaves that are soft and thin. Leaves can be easily damaged. Flowers with entire or lobed lips appear in a variety of colors in racemes on straight stems rising to as much as 4’ tall.
Genus name comes from the Greek word phaios meaning "dusky", in reference to the dark-colored flowers of the type species.
Problems
Good air circulation prevents Botrytis fungus from spotting the flowers. Excess moisture on the crowns may lead to root rot. Water on the leaves may lead to fungal leaf spots. Thrips and spider mites may appear. Watch for aphids on the flowers.
Uses
Phaius orchids are large, spectacular plants that make attractive houseplants. A sunroom is an ideal location.