Odontoglossum oh-don-toh-GLOS-sum

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, humidify. In the levels from 2,000 to 5,000 foot-candles are home, set the acceptable as long as heat levels can be kept plants on trays down. If summer day temperatures are high, above moist pebbles, light levels can be reduced to cool the grow- with the pots resting ing area. While these are not generally above the water. considered to be good houseplants, they may succeed at an east window or a shad- FERTILIZE regularly with a dilute ed south window; western exposures are solution while plants are actively growing. usually too warm in most climates. Applications of 30-10-10 formulations twice a month are ideal for plants in a TEMPERATURES must be exacting bark-based potting medium. A 20-20-20 for these plants. Day temperatures below formulation should be used on other media. 75 to 80 F are almost essential year round. If weather is overcast, applications once a Night temperatures of 55 to 58 F are best. month are sufficient. Some growers use a Short periods of warmer day temperatures high-phosphorus 10-30-20 blossom-booster may be tolerated, especially if humidity formulation as plants approach flowering and air movement are at optimal levels, to increase flower count and substance. nights are cool and the plants have healthy root systems. POTTING should be done as new growth becomes about half mature, which WATER should be plentiful, coupled is usually in the spring or autumn. These with perfect drainage. The potting medium plants need to be underpotted, so when should just begin to dry before watering. repotting leave only enough room for one This may mean watering every two to to two years of new growth. Underpotting The American Orchid Society is the world’s seven days, depending on weather, pot size also enables the grower to provide the leading provider of information about and relat- and material, and type of potting medium. more frequent watering these plants need ed to orchids. We invite you to join us and learn Accordion-pleating on leaves is a symptom as the smaller pots dry more quickly and about the world’s most fascinating flowers and of insufficient water or humidity. As with evenly when filled with roots. A fine-grade plants. Your membership entitles you to our monthly award-winning magazine Orchids, a other orchids from high-rainfall areas, potting medium with excellent drainage is free copy of our cultural guide Your First odontoglossums are particularly sensitive required; because the medium is kept Orchid and the AOS Orchid Source Directory, a to poor-quality water, which will give poor moist, annual or biannual repotting is nor- 10 percent discount on items purchased through roots and leaf-tip burn. mal. Spread the roots over a cone of pot- The AOS BookShop and Orchid Emporium, ting medium and fill in around the roots and free admission to the International Orchid HUMIDITY, coupled with moving air, with more medium. Firm the potting mix Center in Delray Beach, Florida. should be ideally 40 to 80 percent. Evap- around the roots. Keep humidity high and orative cooling in a greenhouse increases the pot dry until new roots form. American Orchid Society humidity while cooling the air and is high- 16700 AOS Lane Delray Beach, Florida 33446-4351 ly recommended for these orchids in most Tel 561-404-2000 Fax 561-404-2100 climates. Fogging the air or dampening the E-mail [email protected]

Drawing Marion Sheehan/Inking Stig Dalström floor with water also helps cool and Web site orchidweb.org

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