The Christmas cactus (Schlumbergera spp.) is one of those houseplants that everyone seems to have but few people know how to care for. It seems like everyone has that one relative or friend who swears they “just ignore it,” and the silly thing is covered with blossoms for them, right on cue, every single year. What gives?
While Christmas cactuses are known for their vibrant blossoms, sometimes it can seem impossible to get them to bloom!
I promise you, there is no wizardry involved, but you do need to know a little bit about how these plants function. Once you know the basics, it’s easy to have a Christmas cactus loaded with colorful buds every single year, right in time for the holidays.
Understanding Your Christmas Cactus
Before diving into the specifics of how to get your Schlumbergera to bloom, it’s important to understand that the Christmas cactus isn’t actually a typical desert cactus. It’s a tropical epiphyte (meaning it grows on other plants), native to Brazil, where it grows in shaded, humid environments along the coastal mountains.
This information plays an important role in getting your plant to bloom because it means that your Christmas cactus has vastly different needs from a true cactus and your other houseplants. It’s one thing to get a tropical plant to grow in your home, it’s a whole other thing to get one to bloom.
Would it surprise you to know that the plant you own is likely not a true Christmas cactus at all?
It’s most likely that what you have is, in fact, a Thanksgiving cactus, named so because it blooms closer to Thanksgiving than Christmas. These plants are often referred to as holiday cacti these days to avoid confusion. (Or to make things more confusing.) Use the handy photo below to ID your holiday cactus. (The care is still the same.)
Short-Day Flowering Plants
Schlumbergera are what’s known as a short-day flowering plant. To produce blooms, they need to go into a period of dormancy as the nights get longer, and temperatures are cooler, too. All of these conditions trigger the plant to set buds once the days begin to lengthen again.
In their native habitat, this happens naturally in April and May.
But here in the Northern Hemisphere, this coincides with the fall and winter holiday season, hence the moniker – Christmas cactus.
What I’m getting at here is that there’s a trick to getting your Christmas – Thanksgiving – Holiday cactus to bloom.
Provide the Right Light Conditions (All Year Long)
The first step to encourage your Christmas cactus to bloom is to give it the correct amount of light throughout the year. You want to provide it with plenty of bright, filtered sunlight during its growing cycle. This occurs during our spring and summer. A great way to ensure your plant gets enough light (so it has enough energy stored up later on to produce blooms) is to move your plant outside during the warmer months. It’s important to make sure it’s somewhere shaded though. Remember, they aren’t true cactuses, and they will get sunburned from direct sunlight.
In the fall, you need to change things up to trigger blooming.
Starting in mid to late fall, your Christmas cactus needs about 12-14 hours of darkness per day for around six weeks.
This can be as easy as moving your plant to a room that gets less natural light in the day. Or, if you have a large plant that’s harder to move, you can cover it with a black sheet (fabric) during a portion of the day.
As soon as you notice it’s starting to set buds, move the plant back to its normal location with bright, indirect light. (And stop covering it.)
Control the Temperature
The other important factor in getting your cactus to bloom is temperature. Christmas cacti respond to the cooler temperatures that go along with the longer nights. You want to aim for temperatures between 50-55°F (10-13°C) during the night in the weeks leading up to the bloom season.
If you’re having an especially warm fall, this can be tricky. If you move your plant somewhere dark during the day, be sure it’s a cool spot as well. The basement and the garage are both good choices.
Water a Little, Then a Bit More
During that dark phase in the fall, when the plant is dormant, you want to allow the soil to dry out a bit more between waterings. Wait until the top two inches of soil are dry, and then water sparingly.
Once buds begin to appear, you can water more frequently. The soil should be slightly damp but never soggy. Always drain any standing water to prevent root rot. (These plants do not tolerate wet feet!)
Because they grow in tropical environments, they need humidity, which can be hard to come by in dry, heated homes during the winter. One of the easiest things you can do is to place your plant on a pebble tray. It’s simply a shallow dish with pebbles that you keep water in. The water will evaporate, providing your Christmas cactus with the perfect amount of humidity.
Know When to Fertilize & What to Feed With
Far too often, people make the mistake of fertilizing in the weeks leading up to the holidays. This can actually hinder bud formation by providing the wrong mix of nutrients at the wrong time.
During the spring and summer, you’ll want to fertilize normally with a balanced fertilizer meant for houseplants. This will help sustain the plant during its annual growing cycle.
At least once before the dormant phase in the fall, you’ll want to feed your Christmas cactus with a fertilizer specifically meant for flowering plants. I have always had excellent results with Schultz Liquid African Violet Food. (My African violets love it as well.)
Don’t fertilize while the plant is dormant. It uses less water during this time, and you can end up burning the plant’s tender roots.
Once the plant sets buds and begins blooming, you can continue fertilizing at half-strength with the blooming plant fertilizer until it has finished blooming for the season. Resume fertilizing during the spring and summer with balanced plant food during the growing period.
Watch Out for Bud Drop
One common issue that can frustrate Christmas cactus owners is bud drop. This is when the plant forms buds, but they fall off before blooming – incredibly frustrating after you’ve finally got your plant to set buds!
The most common cause for this is something going on in the environment.
- Once they set buds, Christmas cactuses do not like to be moved. Don’t jostle or bump the plant a lot.
- Big temperature swings, especially cold, can also cause bud drop. Keep your plant away from drafts or outside doorways.
- Also, inconsistent watering can leave you with buds on the floor. Make sure the plant doesn’t dry out once it begins setting buds.
(Here are 7 other common Christmas cactus mistakes you’ll want to avoid.)
And that’s that!
Once the plant starts blooming, it will consistently put out more blooms for several weeks if you take good care of it. Just keep watering it regularly and removing spent blossoms. After the holidays, let the plant rest a little (you would be tired, too, after a big display like that).
The great thing about these plants is that once you figure out how they tick, you can enjoy hoards of gorgeous blooms every single year. Happy growing!
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