Odontoglossum and Oncidium intergeneric hybrids are comprised of a large group of orchids from many different genera. The Odontoglossum/Oncidium alliance is very popular among orchid growers due to its cultural flexibility and striking sprays of long lasting flowers. The plants may be grown with relative ease in the home or under a sheltered patio.
Lighting
The Odontoglossum and Oncidium alliance thrives on bright light. In the home, an east or a lightly shaded south-facing window is ideal. Outdoors, place the plants on a covered patio protected from the mid-afternoon sun. Direct morning and late afternoon sun can be tolerated by the plants, provided exposure occurs gradually. The plants need to adapt slowly to the increases in lighting. The 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.
Temperature
In temperate regions, Odontoglossums and Oncidiums may be grown outside on a protected patio covering.
Most Oncidiums and their hybrids are intermediate in temperature preference. For the best results provide nighttime temperatures of 50 to 60°F and daytime temperatures under 85°F.
Odontoglossums tend to prefer cool temperatures. For the best results provide nighttime temperatures 50-55°F and daytime temperature 60-80°F. Place the plants near a cool window in the home. In temperate regions, the plants may be grown outside under protected patio covering.
Odontoglossums and Oncidiums will tolerate higher daytime temperatures if the humidity is increased.
Watering
Depending upon the temperature, Odontoglossums and Oncidiums should be watered about two or three times a week. During the summer, the plants may need to be watered every 2-3 days. The rule of thumb for watering should be as followed : More heat more water, less heat less water.
Odontoglossums and Oncidiums prefer to be kept on the moist side. This does not mean that the plants like to be left in standing water,however try to water the plants early in the day, so that the foliage will be dry by nightfall. To prevent bacterial and fungal disease use Physan 20 once a month.
Humidity
Odontoglossums and Oncidiums prefer 50-65% humidity. Humidity should be increased with higher temperatures. Humidity Trays may be needed for plants grown in the house.
Fertilizer
Odontoglossums and Oncidiums must be fertilized on a regular basis! For best results, use Norman's Optimal Orchid Nutrients every other week. It is recommended to pre-water plants, before applying the diluted nutrient solution if the potting media is dry.
Potting
Odontoglossums and Oncidiums should be grown in either Medium Orchid Bark or Fine Orchid Bark Mix. They should be repotted once every two years. Ideally the plants should be repotted immediately after flowering.
Pests
Common pests associated with Odontoglossums and Oncidiums are scale, spider mites and aphids. X-CLUDE, an encapsulated pyrethrum time-release insecticide is the most efficient method of pest control.
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