Oncidium Orchid Care

Fact Sheet – PC8

1100 W. Moana Ln., Reno, NV 89509 11301 So. Virginia St., Reno, NV 89511

General Information

Oncidiums are becoming very popular because they are easy to grow and have long lasting sprays of small, distinct flowers which often have unique color combinations and a pleasant fragrance. They typically bloom once a year and can be grown in the home as well as in a sheltered area in the garden. Oncidiums have been combined with Odontoglossum and other related orchid types through hybridizing to offer a seemingly endless array of striking color patterns.

Temperature and Light

Most Oncidiums and their hybrids enjoy intermediate temperature ranges: 75°-85˚F day and 60°-65˚F. at night. Most Oncidiums and their hybrids prefer filtered, subdued light (from 1000 to 1500 ft. candles). Oncidiums prefer bright light. Their leaves should be bright green as opposed to dark green or reddish green. Reddish green indicates too much light; dark green indicates not enough light.

Water, Fertilizer and Humidity

Oncidiums should become moderately dry between waterings. Generally, they require more water while the new shoot is growing and less once the bulb has formed. Take care to keep water out of the new growth at the base of the plant. Never allow the bottom of the pot to stand in water. Never use artificially softened water. Plants not actively growing should be watered less; many species have winter rest periods.

We recommend the use of Grow More Premium Orchid Food, Formula 20-10-20 (urea free) at half strength dilution at every watering, year-round.

The ideal humidity for Oncidiums is between 55-75%, but 30-40% is workable. If leaves are growing crinkled in an accordion fashion, it is lacking humidity.  Try giving more water and placing on a humidity tray or bed of gravel.  Misting the plant may help and make sure the water is at least room temperature.

Potting

Repot Oncidiums at least every two years. As a general rule, repot them when the new shoot is two to three inches tall or when new roots appear. All the old mix should be removed from the roots and any dead roots should be removed. If dividing, keep the divisions in clumps of three to five mature bulbs. Medium to fine orchid bark is preferred. The base of the new growth should be potted about 1/2" (no deeper) into the fresh bark. Keep mix barely damp until you see the new roots penetrating the bark and then resume normal watering.