Christmas Cactus Care: How to Get It to Bloom (and Is It a Thanksgiving Cactus?)
A Christmas cactus blooms when it gets long nights and cool temperatures in the autumn: about 13 to 14 hours of uninterrupted darkness a night for six weeks, or nights between 50 and 59°F. If yours isn't blooming, it's almost always sitting in a warm living room with the lights on in the evening. And there's a good chance it isn't a Christmas cactus at all: most plants sold as Christmas cactus are actually Thanksgiving cactus, which blooms a month earlier. Here's how to tell, how to get flowers, and how to keep it healthy the rest of the year.
Christmas cactus or Thanksgiving cactus?
The two are close relatives (Schlumbergera) and are sold under each other's names all the time. Look at the edges of the flat stem segments:
| Thanksgiving cactus | Christmas cactus | |
|---|---|---|
| Stem segment edges | Pointed, with 2–4 sharp teeth | Rounded, scalloped lobes |
| Pollen (anthers) | Yellow | Purple-brown |
| Usually blooms | Around Thanksgiving (Nov) | Around Christmas (Dec) |
If your "Christmas cactus" flowers in November, that's why: it's a Thanksgiving cactus doing exactly what it should. There's also an Easter cactus, a different plant with bristly segments that blooms in spring.
Care for the first two is the same.
How to get it to bloom
These plants set flower buds in response to long nights or cool temperatures. You can use either; using both together is the most reliable.
Long nights. From about late September or October, give the plant 13 to 14 hours of continuous darkness every night for around six weeks. Even a couple of hours of lamp light in the evening can stop buds forming. A spare room that nobody uses at night works, or put it in a closet in the evening and take it out in the morning.
Cool nights. Keep night temperatures between 50 and 59°F until buds appear. Don't let them drop below 50°F, which can damage the plant. A cool porch, unheated room or a windowsill in a cool room works. At cool temperatures the plant will set buds regardless of light.
Once buds appear, move it somewhere a bit warmer (60–68°F) with bright, indirect light, and stop moving it around.
Water a little less during the bud-setting weeks: enough that the stems don't shrivel, but let the soil dry more between waterings.
Why the buds fall off
Bud drop is the most common complaint, and it's almost always a sudden change:
- Moving the plant after buds form, especially to a warmer or brighter spot
- A cold draught or a hot radiator nearby
- Very dry soil, or very wet soil
- Big temperature swings
Pick its flowering spot before the buds appear and leave it there.
Everyday care
Light: bright, indirect light. Direct midday sun can redden and scorch the stems. It's a jungle cactus from Brazilian forests, not a desert cactus, so it doesn't want full sun.
Water: water when the top inch of soil is dry, then let it drain fully. It wants more water than a desert cactus but rots if it sits in soggy soil. Limp, wrinkled stems usually mean too little water; limp, soft stems at the base usually mean too much. Our guide to overwatering vs underwatering shows the difference.
Soil: a fast-draining mix. Cactus mix with some regular potting soil added works well.
After flowering: let it rest for a month with a little less water, then resume normal care. It flowers best slightly pot-bound, so repot only every two or three years, in spring.
Propagating: twist off a piece two or three segments long, let it dry for a day, and push it into damp soil. It roots in a few weeks.
Is it safe for pets?
Yes. The ASPCA lists Christmas cactus as non-toxic to cats and dogs, which makes it one of the best holiday plants for a pet household. The same isn't true of everything in the Christmas aisle; see Christmas plants toxic to pets.
If you're not sure which holiday cactus you have, Planted can identify it from a photo and give you a care plan.
Common questions
Why is my Christmas cactus not blooming?
Usually because its nights are too warm or too bright. It needs about six weeks of 13 to 14 hours of darkness a night, or nights between 50 and 59°F, to set buds.
How often should I water a Christmas cactus?
When the top inch of soil is dry, typically every one to two weeks indoors. Let excess water drain away and never let it sit in water.
How can I tell if I have a Christmas or Thanksgiving cactus?
Look at the stem segments. Thanksgiving cactus has pointed teeth on the edges and yellow pollen; Christmas cactus has rounded, scalloped edges and purple-brown pollen.
Is a Christmas cactus toxic to cats?
No. The ASPCA lists Christmas cactus as non-toxic to cats and dogs.