A natural orchid cycle generally sees leaf growth in summer and early fall, a peak bloom in late fall or early winter, and then bloom in early spring. Some orchids will bloom for several months before the flowers wilt and fall off.
Orchid flowerscan fall for approximately 6 to 10 weeks, as the orchid reacts to changes in season with different levels of light and temperature. This is part of the orchid's natural cycle and doesn't necessarily indicate a sign of stress.
If your orchid is exposed to insufficient light, its flowers may fall off unexpectedly. This requires exposure to an east or west facing window. Heat shock can cause buds to bloom or burst, so be aware of any significant temperature changes in your home. However, just because your orchid is resting doesn't mean you don't have to care for it anymore.
If you keep your orchid indoors, in a room where the lights stay on 24 hours a day, your orchid loses this important natural signal. Orchids can be affected by a number of diseases and pests, some of which can influence the health of buds and flowers. The difference in humidity causes the orchid to lose water too quickly and the orchid drops flowers as a sign of stress. A flowering orchid can be tempting to care for more than usual, but over-watering is a sure way to kill your plant.
If more than one or two roots creep along the edge of the pot, it may be time to transplant, or even divide the orchid plant to maintain the vigor of flowering.
orchid flowers and budsfall off due to low humidity or if the temperature rises or falls suddenly, most often due to indoor heating in winter or dry air from the air conditioner. Orchids are tropical plants native to forests in Asia, where humidity tends to range between 50 and 80%. While they enjoy having nighttime temperatures 20° F (-6.7° C) lower than daytime temperatures, they do not enjoy fluctuations in these temperatures during the day or night.
If the night temperature in the orchid room is always 71.6°F (22°C), it should drop to 62°F (17°C) over a two-week period. Always water orchids with a generous soak so that excess water flows out of the drainage holes in the base and all pot media is evenly moist. Orchids typically require watering once every 7 days during spring and summer and once every 10 days in winter (read my article, How to Water Orchids to learn how often to water orchids at different times of the year). If roots can't absorb moisture efficiently after transplanting, flowers fall as a sign of stress.
After the flowers on your orchid plant wilt and fall off, you should make the plant care setting changes I suggested above. Many orchids will re-bloom several times a year and can live for decades, the oldest plant on record thrived for more than 100 years. In fact, it wasn't until 1922 that Lewis Knudson discovered the possibility of artificially providing the orchid seed with all the nutrients, hormones and carbohydrates it would normally receive from the fungus.