How long do orchids live often depends on two factors: the type of orchids and the care it receives. Typically, you can expect the blooming to last from 3-4 weeks to at most 12 weeks.With the epiphytic kinds, you can make a plan for all year-round blooms with many kinds of orchids. They usually bloom once a year with the blooming period varies from 4 weeks up to 12 weeks. The most common orchids flower season takes place between winter and spring, especially with Cymbidium, Dendrobium and Phalaenopsis orchids.Dendrobium orchids flowers can last up to 10 weeks. However, Phalaenopsis or moth orchids have a longer blooming season with the old spikes reblooming.The most common type of terrestrial orchids is Chinese ground orchids with pinkish – purple small flowers. The flower cluster includes 3 to 5 flowers, which blooms about 6 weeks.If you bought your flowers in the blooming period, but the blossoms drop and fall off all of a sudden. This might be due to a sudden change of environment relating to light, temperature and moisture.First off, the flowers should receive full sunlight and be away from radiators, especially avoid the gas stove or the garage.Secondly, during the blooming period, the recommended temperature for delicate flowers ranges from 70 to 80 degrees Fahrenheit.Finally, rainwater or distilled water is best for watering orchids with the frequency of once per week. With epiphytic plants such as Phalaenopsis orchids, they are not ground living plants so you mustn’t place them in standing water.However, when your orchids finish their blooming season, the falling flowers is a sign of the dormant stage. Now all you have to do is provide the proper care for a resting orchid to ensure it will flower again.If you realize that the stems turn brown or yellow, the better option is cut the stalk right down to its node. Otherwise, let the flower spike intact and promote the reblooming with the following conditions.First off, move the orchids to the lower nighttime temperature areas which are about 65 to 75 degrees Fahrenheit.Secondly, keep them in clear plastic or glass pot and in the north or east-facing window places to receive enough indirect sunlight.Thirdly, you also need to keep watering the same amount of water once every week.Normally, terrestrial orchids such as Calanthe could be grown in a pot with a mixture of common soil. However, with the more popular type of orchids – epiphytic orchids, including Cattleyas, Vandas, Phalaenopsis, you can put the mixture of bark, lava rocks into the pot and water enough.The lifespan of the orchids is indefinite. With proper care and good conditions, the orchids will live happily up to 20 years. After that, the plants can easily get diseases.If you overwater the orchids, they will get sick and get the roots rot. In this case, to save them, you can cut the diseased parts and place them into a water container.The water grown orchids flowers (or in a vase) also live for a long period of time (60-120 days) with the correct amount of light and enough temperature.