Don’t allow the hot, harsh sun hurt your succulents! Unlike frost (temperatures of 32 degrees Fahrenheit or lower), heat normally poses no threat to succulents. The majority of plants can tolerate temperatures higher than you’re comfortable with, as shown by greenhouse temperatures that rise into the triple digits on hot days, despite the fact that some don’t seem to thrive in temperatures above 80 or 90 degrees F. Succulents, though, can succumb to heat and sunlight. All smooth-leaved succulents, excluding desert cacti and agaves, require sun protection in the summer, especially when the temperature rises beyond 80 degrees.
If you live in an arid climate ~
- Identify the sun’s position relative to your property. In North America, plants growing on the north side of your house will receive the least solar exposure while those growing on the south will receive the most. My garden, which faces east, receives early sunlight and midday shade. West-facing gardens receive early shade and afternoon sun.
- When temperatures are at their highest in the middle of the day, “bright shade” (no direct sun but not deep shade) is great for non-desert succulents. For low-light succulents like haworthias, bright shade is needed. Visit our website’s Shade Succulents page to learn more. View my video about Shade Succulents.
Above: Although robust, the echeverias on the left in the brilliant shade have lost their colour. The borders of those exposed to more sun are red, but they are smaller due to some stress.
- Keep track of where each new plant you purchase was situated in the nursery. Was it in the open or covered by a tarp? It will need to be “hardened off” (shaded, especially in the afternoon) until it acclimates, even if it is a “full sun” succulent like an agave. This kind of exposure is like tanning: Start with 30 minutes of sun, then gradually increase it by about an hour per day.
- Aloes and crassulas need at least a half-worth day’s of sun to turn red and orange, but not so much that the tips of the leaves shrivel or burn. (Read “How to Stress Succulents and Why You Should. “).
Above: Dryness and heat stress this jade (Crassula ovata). To maintain its life, the plant is gently draining its leaves. However, leaves will be plump and greener after irrigation or rain (which could take months).
- Cover exposed, horizontal stems of trailing succulents (aloes, senecios, othonna, and the like) with dry leaves or mulch to prevent burnt stems from impairing the ability of the plants to transfer moisture from roots to leaves.
- Use floating row covers (preferably), shade cloth, old sheets, or temporary shade structures to protect newly installed plants and in-ground succulents prone to sunburn. I employ rusty window screens. In an emergency, place upright leafy tree trimmings next to a plant you wish to preserve, on the side that receives the most sunlight. Or, in keeping with the sun’s movement throughout the day, use outside furniture.
Above: Aloe brevifolia, a stunning but stressed plant, has closed its rosettes and changed colour from blue to pink.
- Learn how plants defend themselves. When the sun becomes unpleasant, succulents can’t flee to the shade, so some species create their own. Succulents with rosettes, such dudleyas, aeoniums, and some types of aloe, close their rosettes to save their critical cores. Lower leaves that become dry but don’t drop off serve a service by protecting flimsy stems from the sun in the summer and the cold in the winter.
- Where shade will be needed during the long, hot summer afternoons, plant trees and plants. (The Companion Plants chapter in Designing with Succulents, 2nd ed., has information on low-water cultivars suitable for succulent gardens.)
What sunburn looks like
The floppy leaves of this agave stretch (and weaken) the cells in those areas that are most exposed to sunlight.
Succulents with white, beige, or black patches have been sunburned, which causes irreparable cell damage comparable to frost. The plant is alright, but scars will endure just as long as the leaf.
These aeoniums generally have sunburn on the underside of their lowest leaves, which they will shed in a few months anyhow. Very effective, wouldn’t you say?
Several months later, the same aeoniums. Only a few scorched leaves are still visible.
It is preferable if the damaged parts are on the outer leaves because fresh growth from the rosette’s centre will eventually cover up burnt spots. In any event, lower leaves naturally wither and fall off, damage or not. Recovery from a sunburn could take several months to a year, depending on the succulent and the time of year.
Related Info:
Summertime Succulent Watering. Okay, everyone is aware that succulents require little water. They aren’t “no-water plants,” though. Even though they might make it through the summer without irrigation… [Read more…]
A heat wave shouldn’t ruin your succulents. Succulents that are exposed to the scorching sun may burn when a heat wave follows cool weather. The beige or brown patches that develop as a result of sunburn cannot be removed. [Read more…]
Succulent Stress Management (and Why You Should). Some succulents exhibit beautiful reds and yellows when exposed to lots of sunlight, but how much “stress” the plants need depends on… [Read more…]
How cold should it be for succulents?
Whether a succulent is a soft or hard succulent determines what temperature it can withstand.
Anything warmer than 32 degrees F will be enjoyable for soft succulents. preferably over 40 degrees.
These plants cannot endure colder than freezing temperatures. Their hefty, thick leaves, which serve as water reservoirs, will freeze and destroy the plant.
Succulents that can withstand the cold can sustain -20 F. The best it can manage is a zone 4 to 5, and let me tell you, that is very impressive.
You must keep in mind that even if they can withstand temperatures below zero, they still like dry soil. That remains constant.
The majority of winters in the contiguous US will not only be dry but also wet and snowy.
THE IMPACT OF TEMPERATURES ON SUCCULENTS
Succulents typically prefer climates with temperatures between 60 and 80 °F. Some people can withstand temperatures as high as 90°F or as low as 40°F. These severe temperatures are occasionally used by gardeners to “stress” their succulents into changing colour. Many succulents, especially soft succulents, can often benefit from high temperatures between 80°F and 90°F to keep their beautiful hues. You’ll notice that many hues will start to get more intense when the temps fall (but remain over 40F). The chilly (but not freezing) temperatures over a prolonged period of time intensify these colours. Be mindful that your succulents can suffer from temperatures that are too high or too low. Never recommend a temperature of 40°F or greater than 90°F.
Your succulents may suffer from sunburn in the summer due to the combination of high temperatures and direct sunlight, which can harm both the leaves and the root systems. You should move your succulents to a shaded place during the warmest part of the day or cover them with shade cloth. People who reside in regions with extremely hot climates might think about planting their succulents directly into the ground as opposed to in containers since soil temperatures remain largely stable regardless of fluctuations in the weather. If you want to grow succulents in containers, pick materials like concrete, terracotta, ceramic, or wood that are excellent at protecting plants from rapid temperature changes. Avoid using metal and glass containers.
Keep the temperature above freezing to prevent frost damage to your succulents over the winter. You can do this by covering them with a cloth or bringing them inside. While some tropical species like Euphorbia and Lithops demand temperatures of at least 50-60F, some cold-hardy species, like Sempervivum, can endure frost and love cool temps from 30 to 40F. Check out the Hardiness information on each of our plant product pages, where we provide thorough information on the USDA Hardiness Zone for each plant, to discover precisely whether a certain succulent variety is suitable for the climate in your location.
How do succulents react to extreme cold?
Since most succulents are accustomed to hot, arid environments, they are particularly hard hit by winter’s frigid temperatures.
Some succulents, like Aloe, Echeveria, and Crassula, require frost protection when the temperature falls below 45 degrees Fahrenheit. The majority of the other species can endure temperatures higher than 40 °F.
No matter the genus, you should never leave your succulents in a freezer. The explanation is straightforward: because succulents hold a lot of water in their leaves, stems, and trunks, when the temperature drops below freezing, the water expands and bursts through the cell membrane. The plant will eventually expire.
The plants can sense fewer days and lower temperatures, which indicate the impending winter. However, by winterizing them, you can deceive your succulent. Before it becomes too cold outside, you can bring the plant inside and give it regular care.
Simply said, the fall is the ideal season to bring succulents inside. You need to keep your plants from detecting the shift in weather conditions, therefore don’t wait until the actual winter.
Are succulents tolerant of the cold?
The fact that many succulents can survive outside year-round, even in snowy climes, surprises a lot of people. We divide succulents into two categories—”hardy” and “soft”—to make it easier for you to choose the best one for your area.
- Hardy succulents: Tolerate frost and can endure temperatures below zero outside. They are perfect for outdoor gardening all year long. Hardy succulents actually thrive outside more than they do inside.
- Not frost-tolerant are soft types. Before temperatures drop below freezing at night, these types must be brought inside. On the other hand, when the warm, sunny weather returns, they are glad to go outside once more.
the USDA Grow Zone finder (based on minimum winter temperature). You may find a plant’s “Cold Hardiness” on the description of each one in our online catalogue. If your zone number is equal to or higher than the plant’s, that variety can endure the entire year outdoors in your environment. The plant will need to be brought indoors before the fall temperatures start to drop if you live in a zone with a lower number than the Cold Hardiness of the plant.
Most of our plants are also sent with name tags that state the lowest temperature they can withstand for easy reference.
Zones 4 and higher are suitable for Sempervivum heuffelii’s growth, however zones 3 and lower are not.
The Effects of Temperature on Succulents and Cacti
Succulents and cacti prefer to reside in the “sweet spot” of temperature, just as is the case with sunlight exposure. These hardy plants can suffer irreparable harm from either extreme of the temperature range, so it’s important to monitor their health and adjust the environment as necessary.
Succulents and cacti thrive most effectively in temperatures between 40 and 80 °F. Outside of this range, little temperature swings are tolerated, but swings of five or more can result in permanent harm. Even more intriguing is the fact that temperatures that are on the edge of the bearable range (about 40°F or 80°F) can operate as “stressors,” positively affecting the plant and encouraging the expression of more vivid hues.
Succulents and cacti should ideally be kept above freezing during the winter to prevent frost damage. While more tropical types like euphorbia and lithops demand minimum temperatures of 50 to 60 degrees Fahrenheit, other cultivars are actually frost hardy and prefer cooler overnight temperatures of 30 to 40 degrees. Searching for “ideal temperature for insert plant name here” on Google is currently the quickest approach to find out what temps are optimal for your plants. Each plant product page will eventually feature our own documentation.
Extreme Cold and Extreme Hot
Succulents and cactus can, you guessed it, freeze when exposed to freezing or below-zero weather! The water that has frozen inside the plant’s cells expands as it thaws, killing the cells by rupturing them. When the plant finally thaws out, the damaged regions will start to decay or scar permanently—a symptom that could take a few days to manifest. To stop the rot from spreading, the best course of action in this circumstance is to remove the afflicted region with a clean razor blade.
It is preferable to relocate your collection under a patio cover or inside of your home while the freezing conditions last in order to prevent damage from frost and freezing temperatures temporarily. A “frost blanket,” which is just a thin piece of fabric designed to protect plants from cold, can also be used to cover your plants. Plants should be taken indoors for the winter or placed in a sunroom or greenhouse with plenty of natural light in regions of the country where cold temperatures last for months at a time (essentially everywhere else save California).
However, heated temperatures can also do harm if they are not controlled, so they are not the only bad guys in this tale. A variety of things can happen to your plants when it becomes too hot (90 degrees Fahrenheit and above), especially when combined with full sun exposure. For example, leaves may shrivel and/or burn, water inside plant cells may steam and explode, and root systems may become fried.
Because soil is not a very good conductor of heat or cold, succulents planted in the ground with developed root systems can withstand high heat and cold more better than those planted in containers. On the other hand, containers easily conduct heat and cold, focusing such extremes on the roots of the plants.
There are always exceptions to the norm, just like there are in everything else in life. Succulents can withstand temperatures well below freezing and temps as high as 100 degrees. Drive about and observe what sorts of succulents your neighbours are successfully cultivating to find out what varieties work best in your specific climate.
Moisture and Extreme Temperatures = Bad News
Extreme heat and dampness are among the most troublesome environmental conditions. You should never put your plants in a situation where they are both hot and damp or cold and wet. Whether in the ground or in containers, plants that are grown in dry soil perform far better than those that are not. The water in the soil might start to steam in exceptionally hot weather, thus “cooking” your plants. Water can obviously freeze in freezing or subfreezing temperatures, harming the root system and producing rot. If you absolutely must water your plants when extremely high temperatures are predicted, try to do so as early as possible, ideally before 7 a.m.
The TLDR (too long, didn’t read) Summary
Average temperatures are much preferable to harsh ones for succulents. Frost damage can occur in cold conditions, whereas scorching and atrophy can occur in hot temperatures. Paying attention to what your plants are saying is the simplest method to make sure they are content. Bring them indoors or wrap them in a frost blanket if they are suffering from frost damage. Move them to a sheltered spot or cover them with shade cloth if they are scorching or wilting.