Phalaenopsis (Moth Orchids)

Growing Phalaenopsis

Light

Moth Orchids are low-light orchids. They require shady conditions as in their natural habitats. Grow your Moth Orchid in a bright window, with little or no sun. An east or west window or near a shaded south window are ideal.

Temperatures

Moth Orchids need a minimum night temperature of 61-66°F (16-19°C) and a daytime temperature of 75-85°F (24-29°C). Night temperatures to 55°F (13°C) are desirable for several weeks in the fall to initiate flower spikes. Fluctuating temperatures can cause bud drops on plants with buds ready to open.

Water

Because of the absence of any water-retaining pseudobulbs, Moth Orchids need a moist medium – never soggy, but never dry. Water regularly throughout the growing season. Reduce watering slightly during the winter. Do not let the roots dry out completely. Avoid letting the plant sit in water. Mist the plant lightly in summer.
Avoid overwatering, and be careful to keep water out of the crown of the plant. Water can collect in the natural depression formed by the arching new leaf, and if coupled with low air circulation, it can cause this tender new growth to rot.
Water only in the morning so that the leaves dry by nightfall. This will prevent rot.

Humidity

Maintain high humidity (50-80%) for most of the year by setting the plant on a tray of gravel partially filled with water so the pot never sits in water.

Fertilization

Feed regularly during the growing season with a proprietary orchid fertilizer but reduce the frequency and/or strength of feeding in winter. Apply a high-nitrogen fertilizer twice a month if bark-based media is used. Otherwise, a balanced fertilizer is best. When flowering is desired, a high-phosphorus fertilizer can be applied to promote blooming. In winter, fertilizer applications once a month are sufficient.

Potting

The best time to repot is in the spring, immediately after flowering, or when new roots with green tips emerge at the base of the plant.
Repotting should be done yearly or every three years, or as the medium decomposes. Moth Orchids must be potted in a porous mix.
To repot, remove all the old medium from the roots, snip off any diseased or dead roots, and spread the remaining roots over a handful of medium in the bottom of a new pot. Fill the rest of the pot with medium, working it among the roots, so that the junction of the roots and the stem is at the top of the medium. Gently ensure the compost is pressed down firmly around the perimeter of the pot. Drain the plant thoroughly and do not allow it to sit in water.

Propagation

Propagate by division. Cuttings or offshoots may be rooted successfully when roots are 1 in. long (2.5 cm).

Pests and diseases

Moth Orchids are generally disease free. Keep an eye out for aphids, glasshouse red spider mite,s and mealybugs.

Tip for reblooming

If a plant is large and healthy but does not produce flowers in a reasonable time, then reduce the temperature by 8°F (5°C) for four weeks, and a flower spike will usually develop.