Low Temperature Tolerance for a Christmas Cactus

Understanding Christmas Cactus

• Even though Christmas cactus belongs to the cactus family, it isn't a desert-dwelling plant. It's a tropical cactus, native to the jungles of Brazil. In its native habitat, you won't find Christmas cactus growing in the ground. Instead, you'll find it tucked into leaf debris in the crotches of tree branches or snuggled into pockets in stone. Christmas cactus is an epiphyte, a plant that naturally draws all its moisture and nutrition from air rather than soil. The warm, humid jungle climate provides Christmas cactus a perfect home. Because it's from the tropics, cold weather can kill it.

Living Outside Year-Round

• Christmas cactus' low temperature tolerance bottoms out just below freezing, at approximately 27 degrees Fahrenheit. The plant survives reliably outdoors in U.S. Department of Agriculture plant hardiness zones 10 through 12. In cooler climates, Christmas cactus should be a houseplant. When grown in the ground or in containers, soil protects Christmas cactus roots and helps keep the plant alive in warm climate winters. Even when roots survive, low temperatures take a toll on Christmas cactus foliage and blooms.

Keeping Buds and Foliage Intact

• Occasional dips below freezing can cause frost damage in Christmas cactus, just as it does in other plants. In warm climates, protect outdoor Christmas cactus when unseasonable cold snaps arrive. Retaining Christmas cactus' flower buds requires more action. Temperatures just under 70 F produce the most abundant blooms. If your container Christmas cactus summers outside and winters indoors, move it in when nighttime temperatures consistently drop below 50 F. Buds may drop anytime temperatures dip below that point.

Enhancing Hardiness With Health

• Healthy roots improve a plant's tolerance to cold and other challenges. Root rot due to overwatering is a common cause of disease and death in Christmas cactus. Sickly, unhealthy root systems easily succumb to cold and fail to support damaged stems and buds. Give Christmas cactus porous, fast-draining soil so its epiphytic roots always have plenty of air. Water it when the soil is dry to the touch, but before it dries out completely. Never allow Christmas cactus to sit in water or become waterlogged at any temperature, indoors or out.