Sunlight and Water Requirements for Orchids

Sunlight

• Dendrobium and Cattleya orchids need bright light, but the plants don’t do well in direct sunlight during the afternoon. Plants will adapt to a southern or western window with a sheer curtain shading the area. Phalaenopsis orchids are suitable for low light conditions and will thrive in an eastern window with a little bit of sun or no sun at all. These orchids do well in homes with artificial light from four fluorescent lights for 12 to 16 hours a day.

Water

• Orchids need water to grow, but how many times you must water the plant in one week will depend on the container, medium, sunlight and temperatures. Plants need water when the soil is slight dry. If you use a bark medium or a clay container, you may need to water the orchid more than once a week. If the temperatures and sunlight are hot, the medium will dry quicker and the orchid will need more water than if the temperatures are cool and the sunlight is not hot. During the rest period after flowering is done, orchids use less water and may be able to go one to two weeks without needing water. Phalaenopsis orchids don’t have a pseudobulb, which stores water, so this orchid species must receive water before the soil dries out completely.

Temperatures and Humidity

• Dendrobium orchids require a night temperature of no lower 52 degrees Fahrenheit and Cattleya orchids need temperatures above 60 degrees. Phalaenopsis orchids need night temperatures of at least 65 degrees. Daytime temperatures should be at least 10 degrees warmer than the night temperatures. Orchids need at least 50 to 70 percent humidity to grow.

Fertilizer

• All orchid species grow better with an application of fertilizer. However, if you over-fertilize the orchid or use the wrong fertilizer for the type of medium the orchid is growing in, you could damage the plant. If the orchid is growing in a bark medium, use 30-10-10 fertilizer because it has a higher nitrogen level, which plants need when growing in bark. Orchids that are planted in medium other than bark will do well with an application of 20-20-20 fertilizer. Feed the plants once a month with full strength fertilizer or once a week during the growing season with fertilizer diluted by half.