Christmas cactus is a plant that many people buy during the holiday season when their buds are just opening, revealing a colorful display. This colorful display leaves those same people wanting more blooms but having trouble getting these cactus to rebloom for them the following years. So, what’s the secret? Christmas cacti and Thanksgiving cacti have certain requirements (temperature and photoperiods) in order to set their buds!
During the summer months give your cactus bright shade, too much direct sunlight will cause discoloration. During the warmer months you can let the soil dry out between waterings. In order to start flower formation, you will need to trick your cactus into a dormancy period.
Once September rolls around you will need to ensure that your cactus is getting at least fourteen hours of continuous darkness each day for about six weeks. Even so much as a porch light can disrupt this important photoperiod and prevent your cactus from setting buds. Some people put a paper bag over the plant or place it in a dark closet. You must also keep the plant cool during this time at about 60-68 degrees Fahrenheit. Once the buds are formed, the photoperiod is no longer crucial and the plant can come out of hiding in the closet. You must still be careful with temperature though, because any severe fluctuations could stress the plant and cause your precious buds to drop.
Now that your cactus is budding you should keep the soil evenly moist. If the soil dries out too much or stays continuously soggy you could see buds drop. Now you can sit back, relax, and enjoy your beautifully blooming Christmas cactus.
Not sure if you have a Christmas cactus or a Thanksgiving cactus? Look closely at the phylloclades (stem segments). Thanksgiving cacti (Schlumbergera truncata) typically have sharper serrations whereas the Christmas cacti (Schlumbergera bridgesii) are more rounded.