How to Get Poinsettias & Christmas Cactus to Bloom
Two of everyone’s favorite plants for the Holiday Season are the Poinsettia (Euphorbiaceae pulcherrima) and the Christmas Cactus (Schlumbergera briggesii or Zygo Cactus)). However, these plants don’t necessarily bloom naturally during the month of December. They are both photoperiodic plants and have to be tricked into flowering at the right time. Poinsettias and Christmas Cactus, as well as other flowering plants such as Kalanchoes, use a photoreceptor protein to sense when seasonal changes are occurring and nights are getting longer.
Starting in October, we need to keep these plants in total darkness for up to 14 hours a day and then place them in bright indirect lightVery few houseplants should be placed in direct sun. High light refers only to bright indirect light since direct sun often burns the leaves of indoor houseplants. An area that is too hot and dry encourages Spider Mites and causes blooms to quickly fade. A northern exposure really doesn't provide enough light for high light plants. These plants need to be placed directly in front of an east-facing window, within 1-3 feet of a west-facing window, and within 5 ft. of a south facing window. A high light area has over 300 ft. candles of light. the rest of the time. This way, we can force them to bloom exactly when we want. Read more about how to care for these plants in the Popular HousePlant section of the website.