Years ago, and I mean like over 50 years ago, a friend gave me a piece of a Christmas Cactus, Schlumbergera, that came from his Grandmother’s plant. I still have this plant through all those years and after at least 3 moves. I now have a few more, and they are always a joy and easy to care for.
A publication from Michigan State University Extension states that “The “trick” to getting Christmas Cacti to bloom in the years after purchasing them comes down to two things: “light and temperature.” In my experience that is exactly correct. My husband and I like having our house on the cool side, and in order to bloom, the Christmas Cactus wants temperatures in the low 60s, even into the 50s. As for light, the plant needs to have 16 hours of darkness and 8 of light for an extended period of time. My sister once asked why her plant never bloomed, and I explained she had it near a window that had a street lamp outside so there was too much light. Just that amount of light can throw the flowering cycle off. The Chicago Botanical Garden suggests covering the plant with a paper bag, but a dark pillow case or dark cloth would also work. Apparently cooler temperatures can also offset some effects of excess light.
There are actually two kinds of plants that are thrown in the Christmas Cactus category – the Thanksgiving Cactus and the Christmas Cactus. My Thanksgiving Cactus, S. truncata, is blooming now. It has been called the “Crab Claw Cactus.” It is easy to identify by the pointy teeth at the end of each segment. The Christmas Cactus, S. bridgesii, has smooth margins on each segment. Blooms are similar and are available in hot pink, yellow, red and white. I noticed several colors for sale at the grocery store last week.
Both the Christmas and Thanksgiving Cactus come from tropical rain forests in Brazil where they are epiphytic, meaning the plant depends on another plant for support but not food, and grows on tree branches. Therefore, the plant loves to be outside in the summer, and this will help it survive our dry houses in the winter. Give it mostly shade and some sun, but not full sun. As for watering, I don’t give it any special care—just a drink once a week from spring to fall, and a drink every week-and-a-half during the winter. I use a diluted-strength worm-casting tea for a weekly fertilizing. My interior plants instructor told us it was better to give plants a weak-strength fertilizer at each watering, versus a big blast once a month. Plants, even those blooming now like the Christmas Cactus, should not be fertilized from December to the end of February.
As for potting soil, just regular potting soil is fine, or a cactus mix will do. In order to bloom, the Christmas Cactus needs to be pot bound. If you pot up to a bigger size, expect to have a couple of years without blooms while the root system fills in. Sometimes the older stems get woody. I wasn’t sure what to do about that but my cats, Tail and No Tail, took care of it. Sometimes as they played they would bump into the plant, and many of those old, woody stems broke off. This was exactly the pruning the cactus needed, so it flushed out very nicely.