Odontoglossum

oh-don-toh-GLOSS-um

These high-altitude orchids from the New World Tropics flourish where cool temperatures prevail year round. Odontoglossums are known for their striking sprays of flowers. Culture is similar for hybrids in this group, some being Odontonia, Odontioda and Vuylstekeara.

Light
should be bright. In a greenhouse, levels from 2,000 to 5,000 foot candles are acceptable as long as heat levels can be kept down. If summer day temperatures are high, light levels can be reduced to cool the growing area. While these are not generally considered to be good houseplants, they may succeed at an east window or a shaded south window; western exposures are usually too warm in most climates.

Temperatures
must be exacting for these plants. Day temperatures below 75º to 80º F are almost essential year round. Night temperatures of 55º to 58º F are best. Short periods of warmer day temperatures may be tolerated, especially if humidity and air movement are at optimal levels, nights are cool and the plants have healthy root systems.

Water
should be plentiful, coupled with perfect drainage. The potting medium should just begin to dry before watering. This may mean watering every two to seven days, depending on weather, pot size and material, and type of potting medium. Accordion pleating on leaves is a symptom of irregular watering or insufficient humidity. As with other orchids from high rainfall areas, Odontoglossums are particularly sensitive to the water quality which will give poor growth and roots and leaf﷓tip bum.

Humidity
coupled with moving air, should be ideally 40 to 80 percent. Fogging the air or dampening the floor with water also helps cool and humidify. In the home, set the plants on trays above moist pebbles with the pots resting above the water.

Fertilize
regularly with a dilute solution while plants are actively growing. Applications of 30-10-10 formulations twice a month are ideal for plants in a bark-based potting medium. A 20-20-20 formulation should be used on other media. If weather is overcast, applications once a month are sufficient. Some growers use a high-phosphorus 10-30-20 blossom-booster formulation as plants approach flowering to increase flower count and substance.

Odontonia Russiker Blutenbaum "Everglades"

Potting
should be done as new growth becomes about half mature, which is usually in the spring or autumn. These plants need to be under potted, so when repotting leave only enough room for one to two years of new growth. Under potting also enables the grower to provide the more frequent watering these plants need as the smaller pots dry more quickly and evenly when filled with roots. A fine-grade potting medium with excellent drainage is required; because the medium is kept moist, annual or biannual repotting is normal. Spread the roots over a cone of potting medium and fill in around the roots with more medium. Firm the potting mix around the roots. Keep humidity high and the pot dry until new roots form.
For details about the potting media used at Kew (Royal Orchid Collection)

on how to grow modern hybrids

Hosted by www.Geocities.ws