Cacti are succulents and as such they store water in their roots, leaves, and stems. Cold-hardy cacti grown successfully in northern areas have many of the same requirements as in southern areas. Depending on where you live, you will need to protect your cacti in the winter months. A safe temperature for most varieties is 50 degrees Fahrenheit or 10 degrees Celsius. Winter conditions challenge cacti plants, especially outdoors, and many will die without proper care. But there are some cacti that can tolerate frost. Those classified as soft succulents are more sensitive to frost and need attention in winter when the temperature drops. Can cactus survive winter? 10 tips for making it through winter will answer your question with these suggestions.
How to Plant for Optimal Results
Cacti like soil that drains quickly; use a mix of 40-60 percent coarse sand, 10 percent compost, and the remainder garden soil to provide the nutrients and conditions they thrive in. Avoid fine-grain sand as it will clog the drain hole in potted plants. Outdoors, plant in raised beds to provide the best drainage.
Can Cactus Survive Winter? 10 Tips for Making It Through Winter
Keep cacti dry during cold winter months. Otherwise, they will develop root rot. Stop watering desert cacti in mid to late September. To winterize potted plants the larger the planter the sooner watering should stop as they take longer to dry out. The soil should already be dry before temperatures drop too low. To expedite this, use a paper towel or newspaper under the drain holes to absorb moisture.
Avoid watering cacti in the fall or winter seasons, the excess water causes them to freeze which will kill the plant. It is best to hold off on watering until the winter weather passes. Plants that are preparing for winter will shrink and take on a different color. This is a normal part of hibernation. If plants look limp in areas with little to no rainfall, saturate the soil but avoid getting water on them to avoid frostbite. For plants grown in greenhouses, a polytunnel, or a covered balcony discontinue watering in late summer to early fall.
Water indoor plants once a month during the winter. A few cactus varieties only require light watering every 4-6 weeks during winter months. Cacti also like a warmer environment, 50 degrees Fahrenheit or 10 degrees Celsius is the perfect temperature. These varieties include:
- Schlumbergera (Christmas and Thanksgiving cactus)
- Rhipsalis Epiphytic (mistletoe cacti)
- Melocactus (Turk’s cap, or Pope’s head cactus)
Outdoor plants do not require much fertilizer, particularly avoid the ones with large nitrogen contents. Specifically, on the fertilizer bag, it is the first number. Nitrogen causes rapid growth in plants. Damage may result in new shoots in harsh winter temperatures.
In areas that freeze, cover outdoor cacti with burlap as late as possible in the season but before a frost. Cold-hardy species can survive in areas that typically get snow. Covering cacti with burlap allows them to breathe while protecting them from wind which causes frostbite, ice, and sun. For zones with warmer winters a canvas tent shelter protects cacti from excess moisture. Insultate cacti with frost cloths, tents, and row covers. Plants in polytunnels should maintain a winter temperature of 41 degrees Fahrenheit or 5 degrees Celsius. Use dehumidifiers in cellars, garages, polytunnels, and greenhouse environments that tend to get damp and cold. In wet regions plant cacti in pots and place under a shelter. Plants in low areas benefit by diverting snow and rain away with a dry riverbed. In the winter months, relocate outdoor potted plants to covered sheds or patios for protection against the elements.
Some cacti can tolerate temperatures of below 20 degrees Fahrenheit or 28 degrees Celsius. They may have hairs or spines that protect them from frost damage. Some expel water, which may cause them to look deflated, but this is done to prevent stem freeze. However, there are many varieties that cannot tolerate freezing or subzero temperatures, check the hardiness zone before planting to make sure they can survive in your area. Most cacti like to be overwintered by being kept dry and cool. Ideal temperatures are between 41-50 degrees Fahrenheit or 5-10 degrees Celsius. These temperatures encourage dormancy during the winter and encourage blooming in the spring and summer months.
Keep Humidity Low
Cacti prefer low humidity of 40-60 percent with good airflow. If the humidity elevates above this it is best to bring the plant indoors. For indoor cacti maintain a high humidity level by placing the plant on a tray of pebbles and watering when dry, never letting it sit in water. Ideal indoor daytime temperatures for cacti are between 65-70 degrees Fahrenheit or 18-21 Celsius and evenings between 55-65 degrees Fahrenheit or 12-18 Celsius. Allow the soil to get very dry between waterings and water just enough to prevent the plant from shriveling. A light watering every couple of weeks is enough during the winter.
Prepare for Precipitation
Heavy precipitation is problematic because too much of it will cause stem or root rot. If this has happened to your plant cut off the rotted area and add drainage to the soil. Protect cacti from this occurring by either covering or bringing them inside. For outdoor plants create a tent with a canvas or plastic tarp to keep the water out during snow or rain.
Use small rocks on top of the soil to provide warmth during the winter and to prevent overwatering.
Ensure there is Enough Light
Albeit the sun is in short supply during the winter, cacti still require sunlight. Give them as much light as possible, a southwest location is best. Grow lights are an option for those who need extra light. Some cacti varieties need only 4 hours of light a day, while others 6-8 hours. Light is not as important to them during the winter as they are in dormancy. For cacti overwintered in dark garages and cellars reintroduce them to light slowly in the spring. Cover plants with a shade cloth for the first couple of days outdoors until they are acclimated to the light.
Allow for Dormancy
Shorter days and temperature drops trigger dormancy. It is during this time that cacti will slow their growth and when they should stop being watered.
Potted cacti should be brought indoors at the end of summer or in early fall. For those planted in the ground leave them where they are as moving them will cause stress. Bring potted plants inside before frost is forecast. Keep cacti in a cool, dry, unheated space no more than 60 degrees Fahrenheit or 15 degrees Celsius, anything warmer may prevent dormancy from occurring. In fact, it instead creates etiolation (stretched growth.) For indoor plants kept in heated areas make sure they are as dry as possible and water only when there are signs of excess shriveling.
Cold-Hardy Types of Cacti
This variety of cacti belongs to the sedum, euphorbias, and sempervivum families. Many can tolerate temperatures of below 20 degrees Fahrenheit or 28 degrees Celsius. In fact, these plants can grow outside all year round and include:
Beehive Cactus (Coryphantha)
Hardy in zones four through eight, this cactus is about 8 inches in diameter and grows in clusters. This frost-tolerant variety has pink flowers that bloom in spring through summer. Its globe shape is covered in spines preventing snow from reaching the stem.
Brittle Prickly Pear (Opuntia Fragilis)
Hardy in zone four, they are great for colder climates, and this dwarf variety works well in rock gardens. However, when they go dormant the distinctive spiny flat paddle shape will look deflated. They rarely need to be watered and do well in sandy soil.
Eastern Prickly Pear (Opuntia humifusa)
Hardy in zones four through nine, its 3-inch flower attracts bees and other pollinators to the garden. Showy flowers turn into red fruits that taste of kiwi, berry, and melon, and the large paddles are also edible, so make sure to remove the spines!
Hardy in zones five through eleven, this cactus can tolerate below 20 degrees Fahrenheit or 28 degrees Celsius and high summer temperatures. They grow from 3-8 feet tall and are deer-resistant. Bright pink and purple blooms attract butterflies and bees. Also, the yellow fruits are enjoyed by a variety of birds and animals.
Old Man of the Andes (Oreocereus celsianus)
Hardy in zone eight and higher, they grow in 2–6-foot columns and are covered in silvery-white spines and hairs protecting them from the elements. Their dark red to reddish-purple flowers turn into reddish-yellow to yellowish-green fruit.
Kingcup Cactus (Echinocereus Triglochidiatus)
Hardy in zones seven to twelve, also known as Claret Cup, this cactus produces 3-4-inch-long flowers that are a favorite of hummingbirds and bees. Additionally, their edible green, pink, yellow-green, or red fruit are enjoyed by animals.
Pincushion Cactus (Escobaria Vivipara)
Hardy in zones four through eight, this cactus yields pink flowers from spring through summer. They are frost-tolerant and grow up to 8 inches in diameter in clusters.
Barrel Cactus (Corynopuntia or Grusonia)
Hardy in zones nine to eleven, its round ball is covered in yellow spines. They grow to 3 feet high and wide but are most commonly 1-2 feet respectively. Yellow flowers bloom from spring through summer and they can live from 50-100 years!
The photo featured at the top of this post is © Meyta/Shutterstock.com
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