Both varieties of holiday cacti require a period of short day-length in order to bloom. Growers control lighting and temperature to the plants forcing them to bloom in time to distribute them to retail sites before the holidays. If you’ve received a holiday cactus over the years, you may notice it doesn’t bloom all year long. By controlling the hours of daylight as well as the temperature you can force the plant to bloom.
For about six weeks, keep the cactus in a cool, dark room. The ideal temperature range is between 50- and 55-degrees F. At these temperatures, the cacti should bloom regardless of daylength. When buds begin to develop you can return the cactus to a warmer room to enjoy the bloom. If buds begin to drop it is likely due to the environment. These cacti prefer bright, but indirect light. Allow the soil to dry between waterings. Avoid fertilizing and repotting during the bloom period. (Cynthia Domenghini)