The Christmas Cactus (Schlumbergera) is a popular houseplant known for its vibrant, late-season blooms that brighten the holiday season. Unlike desert cacti, this species is an epiphyte, growing on trees or rocks in the humid rainforests of Brazil, which dictates its specific care requirements. Successfully re-blooming your plant involves replicating the natural environmental cues—light, temperature, and rest cycles—that trigger its flowering process. Achieving the desired display requires a robust growing period to build up the plant’s energy reserves for the coming year.
Summer Maintenance and Pruning
The active growth phase for the Christmas Cactus occurs during the spring and summer months, which is when you must prepare the plant for future flowering. During this time, the plant prefers a location with bright, indirect light, such as a spot near an east or southeast-facing window, as direct afternoon sun can scorch its segmented stems. Temperatures between 65°F and 75°F are ideal for daytime growth, with slightly cooler nights around 60°F to 65°F.
Proper hydration is important during this period; the soil should be kept consistently moist but never waterlogged, allowing the top layer to dry out slightly between waterings. To fuel the growth of new stem segments, apply a balanced, water-soluble fertilizer monthly from late winter through summer, stopping fertilization in early fall. Pruning should be done in late spring after the plant has bloomed, encouraging a bushier shape and more bloom points by twisting off or cutting two to three stem segments at a joint.
Initiating the Dark Period
The primary factor in stimulating a bloom is manipulating the photoperiod, as the Christmas Cactus is a “short-day” plant that flowers in response to extended periods of darkness. Beginning in early to mid-October, the plant needs 12 to 14 hours of complete, uninterrupted darkness every night. This schedule should be maintained for six to eight weeks, or until flower buds are clearly visible at the tips of the stem segments.
The darkness must be absolute, as even brief exposure to stray light can disrupt the plant’s internal clock and prevent the formation of flowering hormones. An effective method is to cover the plant with a light-proof box or move it to a seldom-used closet each evening, returning it to bright, indirect light for the daytime hours. This dark cycle, simulating the shorter days of late autumn, is the primary trigger for the plant to shift its energy toward reproduction.
Managing Temperature for Bud Setting
While the dark period is essential, cooler temperatures act as a secondary trigger for successful bud setting. To encourage flowering, the plant benefits from a cool rest period that coincides with the darkness. The ideal temperature range during this six- to eight-week phase should be between 50°F and 60°F (10°C to 15°C), with nighttime temperatures being the most important.
Temperatures above 70°F during the night can inhibit bud development, even if the plant receives the proper dark period. Finding a cool, draft-free location, such as a garage or unheated spare room, can help achieve this thermal requirement. During this cool rest, reduce watering significantly, providing just enough moisture to prevent the stem segments from shriveling.
As soon as small flower buds appear, usually in late November or early December, the plant can be moved back to its normal, warmer display location. Avoid placing the plant near cold drafts or heat vents, as sudden temperature fluctuations can cause the newly formed buds to drop prematurely. Once buds are present, continue to water more regularly to support the energy demands of flowering, maintaining a slightly moist soil.
Post-Bloom Care
Once the holiday display is complete and the flowers have faded, the Christmas Cactus naturally enters a brief rest phase to recover energy expended during blooming. This period typically lasts for four to six weeks in early winter; reduce watering and stop fertilization entirely. The plant should be kept in a cooler location, similar to the temperatures used for bud setting, to simulate its natural post-flowering dormancy.
When new growth is observed on the segments in late winter or early spring, it signals the end of the rest phase and the beginning of the next growth cycle. This is the time to resume regular watering, gradually moving the plant to a location with bright, indirect light. Begin monthly fertilization to replenish nutrients, ensuring the plant is robust and ready to be triggered into bloom again.