Cattleyas are among the most grown orchids, and their culture is often used as a comparison with other types of orchids. Like most other cultivated orchids, cattleyas are epiphytes or air plants that grow on top of trees. They have water-storage organs called pseudobulbs and large, fleshy roots.
Mature plants need a 15 to 20-degree F difference between night and day. Temperature at night should range from 55 to 60-degrees F.; daytime temperature should be 70 to 85-degrees F. Cattleyas can tolerate temperatures up to 95 and 100-degrees F if shading, humidity and air circulation are increased.
Cattleyas grow and flower best in strong, dappled sunlight. They like full sun in the morning but will require shading from about 11 a.m. – 3 p.m.; less shading is essential in the late afternoon. Their leaves should be medium olive green; a darker green color indicates too little sun. Under lights, place four 40-watt fluorescent tubes and two 40-watt incandescent bulbs directly over plants. Plants should be naturally upright, without need of much staking, and of a medium olive-green color. Dark green, limp foliage indicates too little light. Keep out of cold, dry air while in bloom.
Water, Fertilizer, and Humidity
Plants must dry out between watering (they are used to drying out between the rains in their natural habitat).
Feed weekly with a dilution of half the recommended rate of high nitrogen rich 30-10-10 fertilizer, adding SUPERthrive (1 drop per cup or ¼ tsp. per gallon of water). Cattleyas need 50 to 60% humidity. In the home, place on trays over moistened pebbles or use a humidifier if conditions are too dry.
Repot Cattleyas every two to three years in the spring before plant mix breaks down. Pot them firmly in a porous container with good aeration and ample drainage; allow enough room for two years’ growth. We recommend planting them in pre-moistened Kiwi premium-grade pine bark from New Zealand. After repotting, water the plant immediately with warm water and SUPERthrive according to above rate.
Our source for much of this information is the American Orchid Society Guide: Growing Orchids.