No need to worry in summer, practical solutions are here

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Images and text: Aha

Keeping succulents alive through summer is an old, oft-repeated issue. Actually, getting through summer isn't that hard; it's simply a matter of temperature, outdoor growing, scorching sun, insects, mealybugs, black rot, medication, ventilation, and other issues. A brief word on my personal views, hoping to help everyone get through the upcoming summer smoothly.

Sedum: Basically a variety that can spend summer outdoors without pressure, represented by Sedum rubrotinctum (jelly bean plant). What needs attention is the timing of watering, preferably at night, to avoid water on the leaf surface being burned by sunlight, which causes black spots and leaf drop. The Dongsun series (Echeveria) is robust by nature and can withstand high temperatures and scorching sun, but its leaves have a very high water content, and the leaves are tightly packed together, so mushiness and rot are most likely to occur in this type.

Moreover, the most troublesome thing is that once rot appears, it black-rots directly from inside the stem, and measures like beheading or leaf propagation come too late. So, with the rainy season approaching, it's better dry than wet; remember, ventilation, ventilation! Variegated types are albino mutations, and their own chlorophyll content is lower than that of normal plants, so they are relatively weaker in both growth and hardiness. Therefore, this type of variety generally fears heat and cannot tolerate sun exposure, and usually needs extra protection, with shading starting appropriately to avoid the midday scorching sun, because once sunburn occurs and then meets summer's growth stagnation period, it is basically very hard to recover, lingering on until it withers away.

Echeveria: At extreme high temperatures of 37°C, above 38°C, growth of course stops. Actually, any plant will go dormant when it meets too-high temperatures, reducing consumption; this is a form of self-protection. In summer, if there is a temperature difference and ventilation, water should still be given. What needs reminding is that in hot, humid weather, no matter how dry the soil is, don't give water; wait until the stuffy, hot weather passes, then give a small amount, either along the pot wall or by quick soaking, depending on personal habit.

Sempervivum: Absolutely a winter-growing type, dormant in summer, and it sleeps quite deeply. What's comforting is that most of this genus is fairly tough; it generally won't die out entirely unless there's heavy rain and scorching sun. To be safe, shade it and cut off water until it revives in autumn. What needs reminding is that this variety is a stronghold for mealybugs, so spray promptly to prevent pest outbreaks from becoming too widespread. Crassula: A variety you both love and hate. What needs reminding is that there should be no water on the leaf surface; water droplets meeting sunlight will cause blackening and leaf drop, especially for some small types with compact leaves, such as Crassula 'Buddha's Temple' and Crassula 'Ivory Pagoda' and the like, which need strict water control.

In July, simply cut off water and shade, to prevent the bottom leaves from blackening and rotting and ultimately dying. Dudleya: Just think of its place of origin and you'll know it's a variety that fears heat. In summer, cut off water, shade, ventilation, ventilation, ventilation! Aeonium: Summer dormancy; some leaves will basically drop, leaving a bare head. As long as the stem doesn't rot, it will sprout new leaves in autumn and grow rapidly. This genus also belongs to the deep-sleepers of summer, so once it's asleep, just cut off water entirely; it won't die of drought.

Rosularia: Not many people grow it; a robust variety that can tolerate low temperatures, and it propagates very quickly during the growing season. The native species of Rosularia in Xinjiang can tolerate high heat. Small, thin-leaved Rosularia varieties need to avoid strong light, or they will be completely scorched dry in a single afternoon! The rest, such as Pachyphytum, Graptopetalum, Pachyveria, and Adromischus, can be treated like Echeveria. Kalanchoe is completely unafraid of sun but fears freezing; below 0°C, hurry it indoors! The time of year when diseases and pests are most likely to occur is summer. Succulents easily develop all kinds of problems in high-temperature environments, but these problems are not unsolvable. After all, many succulent varieties have never seen high temperatures above 30°C in their native habitats.

So, wanting your succulents to stay in very good condition in summer is indeed not easy, but they are also absolutely not that easy to kill. Due to the limitations of our country's climate conditions, most provinces cannot reach the sunlight levels of the succulents' native habitats throughout the year, with the exception of the western provinces. So most of the time we are in a state of longing for sunny days, especially in provinces that experience the returning south wind (huinantian), where people long for the sun like counting stars and waiting for the moon.

Throughout the four seasons, because the Earth is tilted toward the sun, the sunlight intensity in winter and summer is completely different. For example, today, June 28, is a sunny day with mild pollution, so the sunlight isn't very strong. At noon I measured the sunlight intensity outdoors at about 18,000 lux (a unit of illuminance), and that's through thick smog, so for direct sunlight this is a very low value. In summer, when the maximum temperature reaches 26°C, the sunlight intensity measured outdoors is 80,000, so the difference in sunlight intensity is very large. Sunny days and cloudy days are different, and different air cleanliness also causes different sunlight intensity.

Everyone should be familiar with the tomato, that is, the tomato (fanqie). The tomato and the beautiful Echeveria are from the same hometown; their hometown is Peru in South America. What's different between tomatoes and succulents is that tomatoes grow directly under the sun and are a truly full-sun plant.

But succulents generally grow in valleys on east- or north-facing hillsides. So sun-loving succulents are far behind tomatoes in this respect. When sunlight intensity reaches about 30,000 to 40,000 lux, tomatoes need to prepare for shading. Even a plant as tough as the tomato cannot resist the big sun of our China in midsummer. Succulents are even less able to; without shading there's no hope. This does not include Euphorbia and cacti, which are just too tough. So growers who grow outdoors must start building shade structures; on balconies, prepare hanging shade nets; growers on south-facing and west-facing windowsills, please prepare heat-insulating stickers and the like; those with east-facing windowsills and balconies are lucky,

because the arrival of summer means the east-facing windowsill becomes the best spot for growing succulents. Enjoy life. Shading work must use actual light intensity as a reference. After hanging the shade net, it's best to actually test it; the sunlight after shading should feel warm and comfortable, like the warm sun of winter, and that's just right.

Shade nets come in many specifications. Better to shade a bit too much than not enough, after all, the shade net is configured for those few days of 39°C high temperatures. A movable shade net is best, so that during continuous rainy days the succulents can still see the daylight. Next is high temperature; high temperature is a more terrifying killer than the scorching sun. But the high temperature mentioned here is not just air temperature. Actually, 39°C air temperature really isn't a big deal for succulents. The succulents' own transpiration cooling system can effectively control leaf temperature. If you don't believe it, go touch them; most of the time, succulent leaves are cool. What they truly fear is soil temperature and leaf surface temperature staying persistently high. Completely dry soil is the chief culprit in soil temperature rising. Under normal circumstances, soil also relies on water evaporation to dissipate heat and cool down. Dry soil temperature rises especially fast.

At 3 to 4 in the afternoon, the sun shines almost directly on the side of the flowerpot. If a dark-colored flowerpot cannot dissipate heat through evaporation, it will quickly heat up to above 40°C. If it rises to a high temperature of 50°C, the root system will lose its ability to respire, causing the succulent's life activities to enter a vicious cycle. In summer, even dormant succulents absolutely must not have their water cut off.

But watering has its techniques. Don't water directly until thoroughly soaked; instead, water along the edges of the pot. If it's a very small pot, such as a black square pot, just slowly pour from one corner, letting the water spread slowly through the pot by siphon action, achieving the effect of creating breathable moist soil. Personally, I don't advocate using the soaking method for watering in summer. It's not that soaking is bad, but soaking is a very troublesome matter and requires a lot of technique. If soaking lasts too long, it will create an overly wet situation at the bottom.

When it's hot and evaporation occurs, the whole pot becomes a steamer, and black rot is especially likely. Pots suitable for soaking are relatively large pots with a thick layer of drainage stones at the bottom. For soaking this kind of pot, you can control the water volume so that the water just soaks through the drainage stones. For small pots, it's more reliable to use a narrow-spout watering can. If the weather is clear and dry, excessively high air temperature isn't a big problem either. As long as you spray water on the ground and on the platform where the plants are grown, plus use a fan to blow air, you can lower the temperature by several degrees. Even on an open terrace, splashing water plus blowing air will cool things down without fail.

Pay special attention to weather changes. Cut off water before it rains; the humid air will protect the succulents' roots from damage, and after the weather clears, the air will quickly return to dry. Make sure your soil mix is reasonable, so that even after thorough watering there are enough gaps for the succulents to breathe. Also, after the sun comes out, make sure air humidity is reduced as much as possible, so that water vapor in the potting soil can escape. The best way is to blow a fan.

Regarding pests and diseases, it's best to use systemic medications. Whether for prevention or treatment, use systemic medications. One application can make your succulents toxic for the next month. This can effectively control the occurrence of disease and prevent outbreaks. Apart from a few uniquely favored provinces, summer in most regions won't make your succulents beautiful. Don't pursue beauty; staying alive is the most important thing.

If your home has the conditions, don't insist on growing outdoors in high temperatures. After all, our indoor temperatures rarely exceed 30°C, which is quite pleasant compared to outside. There are also far fewer pests and diseases indoors. If possible, sleeping with the air conditioner on at night can let your succulents enjoy a temperature difference of about 10°C. Then you can not only get through summer smoothly, but also indulge in the hope that your succulents will show their colors.

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