Holiday cacti are festive plants that bloom during the winter months, and cool conditions are required for their eye-catching, colorful blooms to form.
But since they aren’t cold hardy, it’s important to know exactly what temperature range they need to thrive and promote blooming.
Whether you’ve just received a Schlumbergera as a holiday gift, or have inherited one of these long-lived succulents from a friend or relative, you may be wondering if it’s safe for this plant to spend time outdoors when the conditions start to cool.
Perhaps you’re trying to figure out if your Christmas cactus can live outdoors all winter long.
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That will depend on just how low the temperatures fall in your location during the colder seasons.
And although they aren’t cold hardy, it might surprise you to learn that cool conditions are actually required to help these succulents flower!
In this article we’re going to clear up any confusion you might have about Christmas cactus cold tolerance. Here’s what we’ll cover:
Cold Tolerance of Christmas Cactus
Since you’re here to learn more about the cold tolerance of Schlumbergera, it will benefit you to have a greater understanding of their overall temperature preferences to give you a complete view of their seasonal needs.
Before we get started, if you’d like to dip back into the basics of these succulents including their background, care and maintenance needs, and tips on pest and disease control, be sure to read our complete guide to growing and caring for Christmas cacti.
Best Temperatures for Foliage Growth
These cool-weather blooming epiphytes hail from coastal, mountain forests in Brazil where the conditions are fairly mild.
In the warm months, the daytime range tends to stick to a pleasant 70 to 80°F, with drops of about 10 degrees at night.
In temperatures up to 90°F, holiday cacti are stimulated to produce their distinctive foliage that consists of flattened stems, known as cladodes – but not blooms.
If temperatures remain above 90°F, they’ll stop growing and wait for cooler conditions before resuming growth.
Best Temperatures for Bloom Production
Next let’s look at the ranges that will encourage these succulents to bloom.
While not all gardeners are in agreement on the ideal temperature range to encourage flowering, most horticulturalists agree that nighttime temperatures of 55°F is appropriate to encourage bud formation.
On the other hand, below 50°F can cause buds to drop, and nighttime temperatures consistently above 65°F can prevent bud formation.
That gives us a sweet spot of nighttime temperatures between 50 to 65°F if you want your holiday cactus to bloom.
Or aim for 55 to 60°F if you want to be more prudent on both ends of the range, avoiding points on the thermometer that may be either too cool or too warm.
You can learn more about how to encourage Christmas cactus to bloom in our guide.
Christmas Cactus Cold Tolerance
While not all gardeners aim for the same range on the thermometer to encourage flowering, likewise, not all horticulturalists designate the same cold tolerance for these succulents.
This is likely because cold tolerance for any given plant depends on more than just the temperature – other factors that influence this tolerance include length of exposure, humidity, and soil dryness.
In fact, some succulents, such as prickly pears, are much more tolerant of the cold if conditions are fairly dry.
However, this is not the case with Schlumbergera species as they aren’t adapted to living in cold winter conditions.
The coldest these succulents experience in their native range is around 50°F, so this is a good lower limit to respect.
So if your plant is outside for the summer, be sure to bring it back indoors before the forecast predicts it to drop below 50°F as if it goes any lower Christmas cacti can drop their leaves.
Having said that, some gardeners – and even some well-respected gardening institutions – claim that these plants are hardy to USDA Hardiness Zone 10, where lows can reach 30°F.
Others recommend this plant for Zone 11 at the coldest, which experiences lows of 40°F.
As we’ve discussed, it’s likely that these differing opinions on the cold tolerance of these succulents reflect other environmental conditions as well as temperature.
Humidity differences will affect this tolerance, as will the hydration of plants when exposed to temperatures below 50°F. So unless you have personal experience that tells you otherwise, play it safe and keep plants above 50°F.
Do you live in a location where weather conditions stay above 50°F during winter?
If so, you may want to read our article about growing holiday cacti outdoors.
I mentioned the importance of length of exposure to freezing conditions.
If you are bringing one of these holiday bloomers from a car to your front door during winter, keep the plant in a bag or box to protect it, but it should be fine for such a short length of time.
On the other hand if you leave one of these houseplants outdoors for an entire night of freezing conditions, you may find the stems have turned mushy the next morning.
Cross your fingers – although it will be severely damaged, there’s a chance you may be able to revive the plant!
To do this, move it out of the cold and into a warm – but not hot – location. Trim back any damaged stems – anything that is mushy or black – and give the plant a small amount of water if the soil is dry.
Maintain even moisture in the soil to keep the roots alive, but don’t water abundantly until stems begin to regrow – if indeed they do regrow.
Only time will tell! You’ll have to wait and see if the plant recovers and produces new stems later in winter or spring.
Chill Out – But Not Too Much
Let’s do a quick recap: keep these succulents above 50°F to prevent cold damage.
Aim for 55 to 60°F to encourage blooming, give them 70 to 80°F to promote stem growth, and never expose them to freezing conditions for extended periods.
And if a holiday cactus is exposed to a night or more of freezing temperatures, prune damaged foliage and try to keep the plant alive until it begins to regrow.
Do you have any remaining questions about the cold tolerance of these epiphytic succulents? Are you growing a holiday cactus outdoors year round? If so, what USDA Hardiness Zone are you in? Let us know in the comments section below.
Want to keep learning about growing holiday cacti? We have more reading for you right here:
