Oncidiums, Brassias and Oncidium Intergenerics

Many varieties of this group will bloom more than once per year, however spring is usually the peak flowering season. Many of them are fragrant, in particular Miltoniopsis, Brassias and a few Oncidiums.


Good light is most important when growth is maturing. If you are growing plants in a cooler temperature, then it is recommended to increase the light level. Usually a bright west or east window, or filtered south window is ideal. Towards the center of 4 foot fluorescents is also good for smaller plants, if you are growing under lights.


Intermediate conditions suit most varieties. If you are growing them under warmer conditions, then reduce the light level to compensate. Odontoglossum types typically prefer cooler conditions.

Water and Humidity

Allow to dry for 1 day between waterings. Once per week is usually sufficient. Plants prefer to be underpotted. Miltoniopsis are mostly intermediate growers, but they should have good humidity to avoid pleating of the leaves. A high-quality sphagnum moss helps to attain this, and the fine roots of this group appreciate the extra moisture. Try not to let them dry out for extended periods, as the leaves will either pleat or start to go limp and leathery.

The plants we sell from this group are usually in sphagnum moss, in 2.5 inch pots. Watering thoroughly once per week is adequate for intermediate household temperature and humidity. This regimen suits the plant for about a year, at which point the plant will likely be at the edge of the pot. When repotting, you have the choice of upsizing to 3 inch pots with a sphagnum/perlite mix, or a fine bark mix. You should either pre-wet the mix you use, or thoroughly drench it after repotting.

Fertilizing and Water Quality

If you are using good quality city water, then fertilize once per 3 weeks at the most, using 1/4 of the recommended strength on the label. If you use rainwater or distilled water, then this can be increased to once every 2 weeks at the most. Only fertilize during active growth periods to avoid burning the roots. Usually this is from February to September inclusive. Make sure to flush the pots every 2 months at least, using distilled or rain water in copious amounts to remove any accumulated salts. Well water must be diluted by at least half by adding distilled or rain water to limit damage caused by excessive minerals.

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