Find how cold Christmas cactus can tolerate, how to protect it from freezing, and tips for keeping it healthy in cooler temperatures.
When you think of cacti, you probably picture a hot desert with lots of sun. This is true for most cacti, but holiday cacti are different. They actually bloom better in cooler temperatures. These tropical plants need cooler air to form buds, but that doesn’t mean they can handle the cold. Christmas cacti can easily get damaged by cold if they are in drafty or cold areas of the house. Find How Cold Christmas Cactus Can Tolerate.
Christmas Cactus Cold Hardiness
Holiday cacti are popular houseplants that bloom around the holidays. Christmas cacti usually flower in winter, producing bright pink blooms. Outside, they can only survive in USDA zones 9 to 11. So, how cold can a Christmas cactus tolerate? While it can handle cooler temperatures better than some other cacti, it can’t survive frost. These tropical plants need cool temperatures to bloom but prefer warm, mild conditions. They also like moderate moisture and bright sunlight. Keep them away from things like drafts, heaters, and fireplaces. The ideal nighttime temperature for a Christmas cactus is between 60 to 65°F (15-18°C).
To make your Christmas cactus bloom, move it to a cooler spot in October, where the temperature is around 50°F (10°C). Once it starts blooming, avoid sudden temperature changes, as this can cause the flowers to drop. In summer, you can take the plant outside, but make sure it’s in a shady spot and protected from the wind. If you leave it outside too long in the fall, it could suffer from cold damage.
How Cold Christmas Cactus Can Tolerate
To find the answer to this question, you are required to look at the growing zone. The U.S. Department of Agriculture (USDA) has hardiness zones for plants, which show the average minimum winter temperature in each zone.
Each zone is 10°F (about -12°C) apart. Zone 9 ranges from 20 to 25°F (-6 to -3°C), and Zone 11 is between 45 to 50°F (7-10°C). This shows that Christmas cacti can handle a range of temperatures, but they definitely can’t tolerate frost or snow. The pads will likely get damaged if the plant is exposed to freezing temperatures for too long.
How to Treat Christmas Cactus Exposed to Cold
If the cactus stays in freezing temperatures for too long, the water inside its tissues will freeze and expand. This can harm the cells in the pads and stems. When the ice melts, the tissue shrinks and becomes damaged, causing the stems to go limp, leaves to drop, and spots to rot. If your Christmas cactus has been exposed to the cold, be patient when treating it. Start by removing any parts that look badly damaged or rotten.
Water the plant lightly, but don’t let it sit in water. Keep it in a spot around 60°F (15°C)—warm but not too hot. If the plant survives for six months, you can start feeding it with diluted houseplant fertilizer once a month during its growing season.
If you move it outside next summer, remember that Christmas cacti can’t handle freezing temperatures, so bring it inside before it gets too cold.