Strong light (over 2,000 foot-candle) is recommended. Inadequate light levels will result in spindly stems and thin leaves with little or no flowers. East or west windows in the summer and autumn and south windows in the winter and early spring all give plenty of light to grow dendrobiums well. Extended exposure to strong light or abrupt exposure of plants to high temperature in the presence of strong light can quickly cause permanent sunburn.
Cattleyas can tolerate a wide range of temperatures, anywhere between a range of 65-80 degrees should lead to optimal growth.
WATER AND FERTILIZER
Depending on the media it is grown in, most orchid growers will start cattleyas growing in a very loose medium that does not hold a lot of water such as lava rock. Cattleyas do not like to be overwatered and can easily get bulb rot. More mature plants that are larger in size with a significant root system can handle growing in wetter mediums like moss. Looser material like lava rock may require watering 2-3 times a week with fertilizing happening every week since lava rock will not hold much. If it is potted in moss, only water when the medium is dry or getting dry and fertilize only once a month with a even mixture water solube fertilizer like 20-20-20 using 1/4 teaspoon per gallon dillution.
Cattleyas often grow in a line like runner plants and will start to make a b-line for the edge of the pot. When repotting try to save as much of the roots as possible. If the plant is large, you may divide the plant and pot each division seperately with at least 4-5 bulbs that are connected in a line. Do not seperate each bulb, they must be together!! If repotting only a few bulbs it is better to use a looser material and allow more roots to grow before switching to wetter media. If you are trasferring a cattleya without division, it is ok to use a wetter media but be careful not to overwater while the roots are recovering and filling the media.