Your holiday cactus will need some special treatment to make sure it will rebloom this year.
“Given proper care, holiday cacti can provide years of brilliant color around the Thanksgiving and Christmas holidays,” said David Trinklein, a University of Missouri Extension horticulturist.
“Holiday cacti are short-day/long-night plants that need a long, uninterrupted period of darkness to be induced to bloom,” Trinklein said.
The most prolific blooming happens when plants can dry out and have at least 13 hours of darkness each night in cool temperatures. Beginning in mid-October, place your cactus where it receives no artificial light from sundown to sunrise. Continue this regimen until buds start to form, he said.
Flowering will occur regardless of day length if the cactus is exposed to night temperatures of 50-55 degrees. “Unfortunately for our cacti, this temperature range is considerably lower than most people maintain in their homes,” he said.
Reducing the amount of water to slightly stress the plant will help the plant bloom. Too much stress, however, in the form of under- or overwatering or sudden changes in temperature might cause the cactus to drop unopened flower buds.
Poor flowering is often due to stray light interrupting the required long periods of darkness. Interior lights in the home, streetlights and even car lights can disrupt the dark period and cause disappointing flowering.
Holiday cacti are also very prone to root rot, which can lead to bud drop and plant loss. Avoid excessive watering and maintain strict sanitation when culturing the plant. Holiday cacti need repotting about every three years. Use a porous, well-drained growing medium. Commercially available peat-lite mixes formulated for epiphytes are good choices.
“The small amount of effort required by these plants is well worth it when you consider the reward of seeing an ‘heirloom’ plant bloom year after year,” Trinklein said.
