Growing cotton earns 200,000 yuan a year, so why are many people unwilling to grow it anymore?

The original video text is as follows:

When people mention **, many think of specialty vegetables, fruits and melons, and cotton. ** has a high-quality long-staple cotton production base. Every year the cotton is transported to the mainland and even exported abroad, and cotton is also called “white gold.”

Local farmers have been growing cotton for more than 30 years, prices have been relatively stable, and many farmers earn 200,000 yuan a year. But recently, farmers have not been very enthusiastic about growing cotton. Instead, many farmers are unwilling to grow it and want to go out to work. Why is that? Cotton is so profitable, so why is no one growing it? In fact, young people in rural areas today have received higher education, and many children choose to stay in the city after graduating from university and work there. This phenomenon leads to a shortage of labor in rural areas, and it is difficult for rural areas to develop further. In addition, the recent continuous decline in cotton prices and the impact of extreme weather have meant that income can no longer support a family's living expenses.

One cotton farmer said he planted 60 mu of cotton. The current price is 2.6 yuan per jin. After deducting costs, he takes home only a few thousand yuan. Many farmers who plant more than 100 mu earn only 30,000 to 40,000 yuan. So for cotton farmers, this is also a very serious problem.

Ginkgo Ginkgo biloba L. Ginkgo illustrated guide: how to grow ginkgo / how to propagate ginkgo

Home Cultivation of Succulents (Superb and Comprehensive)

Many people should find the following article both familiar and unfamiliar. Familiar because some chapters and paragraphs seem to have been seen before; unfamiliar because many who have read it do not know its source. In fact, these wonderful passages all come from http://blog.sina.com.cn/zym004361. The author Jiang Fengliao systematically and comprehensively introduced various knowledge about home cultivation of succulents, such as: light, temperature difference, watering, medium, etc. Although it is an article from 2011, it remains excellent even today. If one were to read only one article on home cultivation of succulents, this would probably be it. The full text is more than 30,000 characters, and every word is worth reading carefully.
Introduction:
For the cultivation of succulents, I have gone through no more than 3 years from beginning to end. Thanks to the teachings of fellow flower lovers, during these 3 years old Jiang has accumulated a little shallow knowledge, and based on personal conjecture and fabrication, has also summarized some experience. A bottle that is full makes no sound while a half-full bottle sways; half-baked old Jiang always vainly attempts to systematically summarize some secret manuals, tips, and the like, fantasizing about giving back to the public, but unfortunately his learning is shallow and he has never dared to show off before the masters in forums full of experts. Fortunately, there is still a private space on Sina Blog, giving old Jiang's immature reflections a place to see the light. How fortunate.
Jiang knows he is a talker, able to spread a bean-sized matter into a pancake-sized scale, and the article also contains many biased points. Therefore, I respectfully warn all fellow flower lovers: before reading, please prepare tea for yourselves. When you find something tiresome, feel free to leave comments and criticize, but please do not pound the table in anger, lest you disturb the neighbors.
Preface:
South Africa is located in the southern part of the African continent, and most areas belong to the tropical savanna climate type, with rainy summers and dry winters. Due to the influence of the warm Indian Ocean current and the cold Atlantic current, the climate differences between South Africa's east coast and west coast are very obvious. The east is warm and humid, while the west is relatively dry. Because of this, the terrestrial plant species on the east coast are clearly greater than in other areas. Among them, the more familiar Liliaceae Haworthia genus plants (also called the 12-volume genus, Bulbine genus) and most species in the Aizoaceae family grow on South Africa's east coast.
As for the cultivation of succulents, old Jiang's involvement is not very deep. His main research direction is the two types mentioned above. Although Jiang also has some understanding of Agavaceae plants native to Mexico, due to climate and environmental reasons, from the perspective of cultivation research, Agavaceae plants belong to another system, so they will temporarily not be discussed in the following sections.
There are nearly 3,000 species of succulents in South Africa. The two large genera mentioned above account for at most one or two tenths. The reason the article dares to use such a broad title is not because old Jiang is ignorant and arrogant, but because there is a premise -- namely, home cultivation.
Home cultivation is a cultivation form with a vague concept. Due to limitations of environment and conditions, in a home environment it is impossible to carry out categorized management to satisfy the slight differences in the physiological needs of different plant species. Instead, one can only carry out relatively unified management based on the characteristic that plants from the same origin share relatively greater commonality. For example, the habit differences among varieties of winter-growing succulents are not very large. Although there are many varieties, if one is really serious, 100 plants can have 100 cultivation methods. But if you play dumb and treat them as one variety, serving them the same way, in the end they still grow about the same. This is what old Jiang calls the concept of vague cultivation. The principle of this concept is -- make full use of the available space and raise more plants well at the lowest cost. And it is precisely because of the guidance of this vague concept that this long article could be written.

I. Definition and Characteristics of the Home Environment
The so-called definition of home cultivation does not mean that if this place belongs to your home, it is a home environment. (Now the wealth gap in society is so large that living in a 500-sq-m garden villa and living in a pigeon cage where the kitchen and toilet are all in one certainly cannot be mentioned in the same breath.) In order to avoid unnecessary disputes and eliminate all disharmonious factors, it is necessary to define it here first. What I consider a home environment refers to: amateur cultivation kept only in simple environments such as indoor balconies, windowsills, and flower racks, and without intervention by high-tech means such as artificial chemicals and hormones. Open courtyards, terraces, small greenhouses, etc. are not included. Of course, local use of simple means for heating and humidifying should belong to the category of the home environment.
The main characteristics of the home environment are:
1. Mainly indoor, non-open-air environments, with shelter above, rarely direct sunlight, and lighting mainly relying on diffused light. (Do not think that pulling up a lounge chair and sitting on the balcony in the sun is sunbathing. Light passing through an awning and glass can only be called light, not sunlight. Or you can first go to the street and feel it.)
2. The day-night temperature difference is lower than the theoretical temperature difference in the weather forecast, and the high temperature is not high while the low temperature is not low. The daily high and low extreme temperatures are both close to the local average temperature of the day. If this is not the case, I can only assume you live in a pavilion.
3. The space is relatively enclosed. Air circulation and convection intensity need to rely on artificial intervention. After watering, moisture easily accumulates, but under normal circumstances air humidity does not change much, and the all-day average is lower than the outdoor air humidity average.
4. Most implementers of home cultivation and maintenance are ordinary enthusiasts, not professionals. They do not understand what hormone levels are, what the pharmacological effects of pesticides are, what the physiological structure of plants is, and so on. Of course, a little basic knowledge is still needed. Otherwise, if you grow a Lithops into a long-nosed king and still feel smug about it, that will inevitably affect the popularization effect of old Jiang's long article.

II. Physiological Characteristics of South African Succulents
Because of its special geographical location and strange environmental climate, South Africa's east coast produces succulents with very distinctive personalities. Leaving aside the unique ones, generally speaking, these plants like coolness and dislike heat, but cannot resist freezing point. They like moisture and dislike dryness, but are not accustomed to waterlogging. They like sun and fear shade, but cannot be excessively exposed to strong sun. Finally, the greatest characteristic is that after integrating the above three points and then intensifying them by doing the exact opposite, it still lives perfectly well... Of course, reaching this level also has prerequisites. Under ordinary circumstances, in everyone's homes, tragic events should be happening all the time.
1. Physiological Characteristics of Haworthia Plants
Haworthia plants are winter-growing plants. In South Africa, the local winter from May to August has abundant rainfall and is exactly the growing season. Since they are winter-growing plants, that indicates this species likes coolness. But after all, South Africa is Africa, close to the equator, and its geographical location determines that even in winter the temperature will not be too low. Taking Cape Town, South Africa, as an example, the local winter average temperature is 7 degrees, while during the day in sunlight it generally briefly rises to about 25 degrees, and at night there are occasionally extreme low temperatures of 2-3 degrees. Overall, however, this temperature is much easier to endure than winter in our southern cities. (Both have the character "south," so why is the difference so great? Thinking of Hangzhou's icy, damp bed in winter, old Jiang in the June heat cannot help but shiver continuously...) There are also unfair things: every year from November to February is South Africa's summer, with an average temperature of 26 degrees. Due to geographical environmental influences, low temperatures of around 15 degrees often appear at night. This is what is called a feng shui treasure land, warm in winter and cool in summer. For the vast number of flower lovers suffering from the southern climate, South Africa can absolutely rank first among immigration destinations.
In the native habitat's summer, because rainfall is rare, most Haworthia plants are in a protective dormant state. Very few varieties grow in summer. Apart from a few rare high-altitude species, most other varieties resist intense sunlight and water evaporation by shrinking their bodies and half-burying themselves in the soil. Fortunately, however, because the day-night temperature difference is extremely large and water vapor from the sea often invades the inland, water droplets condense on the plant surfaces at night, slightly moistening the dried-up life. This is also why native Haworthia can continue life under long-term summer water shortage.
Haworthia plants belong to semi-shade plants. Of course, the so-called semi-shade is also comparative. Semi-shade here does not mean they should be kept in sheltered places for a long time, but refers to the degree and duration of light received. From pictures of plants in their native habitat, in exposed rocky areas the number of Haworthia plants is obviously very small, and their condition is not very plump. They can even be described with words such as shriveled and scorched. (Imagine an 80-year-old grandmother in a rural area of the northwest, and you will have a relatively intuitive impression.) Under forests and among grass, the number and appearance of Haworthia plants are relatively more abundant. I believe the main influencing factor is sunlight. Based on old Jiang's accumulated experience and relevant literature references, I believe Haworthia plants are suitable for 3-4 hours per day of medium-to-weak intensity sunlight, which is what we call semi-shade.
Since they are semi-shade plants, relatively speaking their water requirements must also match. Logically speaking, since they fear strong sun exposure, they must fear water loss, so uninterrupted water supply is necessary. But in Africa's geographical environment of sunny heat and little rain, it is destined that the native habitat cannot have abundant rainfall year-round. This requires the plants to have water storage capacity. Having water storage capacity also shows that Haworthia plants also have drought resistance. And generally, plants with several resistances, if given too much all at once, may instead be killed by overfeeding. This is a consensus and can also be regarded as an axiom in this discussion process, requiring no proof. From this, the final conclusion is that Haworthia needs water, but does not need frequent large amounts of water. In plain language -- if water supply is divided into four levels: wet, damp, moist, and dry, then Haworthia should use "moist."
The water storage capacity of Haworthia plants and the soil texture relationship in their native habitat (this is relative to cactus plants native to Mexico) have caused Haworthia to have thick fleshy root systems rather than fibrous roots like cactus balls. Fleshy root systems have a very large oxygen demand. Unlike fibrous roots, most of the function of fleshy roots is to store and transport nutrients, playing the role of a "pipeline." Therefore, their epidermal cells are slightly larger and tighter. The purpose, of course, is to consolidate their physical form, equivalent to strengthening the "pipeline" function. But such tissue often has slow metabolism, and old cells cannot be replenished in time. Dead cells in an oxygen-deficient environment are extremely easy for anaerobic bacteria to use as a breeding ground -- this is why fleshy roots rot easily. But Haworthia's root system is not entirely different from that of cactus balls. They have a very tragic common point, namely extremely low osmotic pressure. That is, salts in the external soil can very easily penetrate into cell tissues, causing cell dehydration. We all know how to cure meat and salt vegetables. A piece of plump fresh meat or cabbage, sprinkled with a handful of salt, will release water all over the floor after half an hour. Leeches are the same; upon encountering salt they dissolve into water. This uses the principle of osmotic pressure. The root osmotic pressure of Haworthia and the like can probably only compare with that of Gasteria and leeches. This is of course related to water shortage in the native habitat. Lower osmotic pressure allows the limited external water to be absorbed more conveniently.
2. Physiological Characteristics of Aizoaceae Plants
Lithops and Conophytum are also representative succulents of South Africa's east coast. Unlike the Haworthia genus introduced above, plants of these two genera mostly grow in exposed rocky areas, exposed to sunlight all day, lacking clothing and food. As long as there are just a few millimeters of rainfall each year, they can happily bear offspring during the reproductive season. But once heaven opens its eyes and sprinkles a few extra drops of rain, it often causes serious consequences of mass rot. Basically, this type of plant is a typical type that does not know what is good for it. The harsher the environment (relative to most plants), the more prosperously it grows.
Compared with Haworthia, Lithops and Conophytum belong to full-sun plants, have semi-lignified root systems with a main root, and have extremely low water requirements (for example, varieties such as Otsu-e have only a few millimeters of annual rainfall in their native habitat). The plants' resistance and ability to withstand external erosion are stronger than Haworthia, especially their tolerance to low temperatures (they can withstand short-term low temperatures of about minus 5 degrees).
What they have in common with Haworthia is that they also belong to the winter-growing type and also have very low root osmotic pressure.

III. Sunlight and South African Succulents' Pursuit of Sunlight
1. The Role of Sunlight
All things grow relying on sunlight; go one day without sunlight and you feel stifled. The ancients, when tormenting prisoners, liked to shut people in dungeons and deprive them of the right to bask in the sun. This shows the importance of sunlight to living things.
Compared with animals, plants depend even more on sunlight, because light can help plants carry out photosynthesis, manufacture nutrients, and supply the whole body. Someone may say, plants have roots; plant roots are what absorb nutrients... I can only say, please find your junior high school biology textbook. What plant roots absorb is only raw material. The raw material must be transported to the leaves, and then through chlorophyll, carbon dioxide, and light catalysis, photosynthesis occurs, ultimately producing sugars that the plant can consume. It is like what flows through your blood vessels is blood, not rice.
Sunlight of course refers to full-spectrum natural light. So-called full spectrum means light that, after prism refraction, can reflect 7 kinds of monochromatic visible light. So-called natural light means composite light that, in addition to visible light, should also include invisible wavelength bands such as UVA, UVB, and UVC. Among these, what mainly regulates plant growth are red and blue light in the visible spectrum, as well as UVA, UVB, and UVC. There are now high-tech red-blue plant growth lamps on the market, said to have good effects, but the cost of use is estimated to far exceed the price of ordinary home-cultivated plants. Just know that such a thing exists and let it go; do not take it seriously.
Old Jiang thinks visible light is easy to understand, but the role of invisible light is often easily ignored. Fortunately, when I previously kept turtles and birds, I understood the components of invisible light relatively deeply. Taking this opportunity, I will squeeze it all out together. Otherwise, with a belly full of learning, if I do not release a big lump, I am afraid I might hold it in until prostate problems develop. Fortunately, the article is not intended to be published on a forum and is only for internal exchange, so old Jiang can write as he pleases, and you can read it or not.
2. Introduction to Invisible Light in Sunlight
UVA, wavelength 320-400 nm, also called long-wave black spot effect ultraviolet. It has very strong penetrating power and can pass through most transparent materials, damaging biological epidermal cells and promoting cell aging. In the human body, it causes tanning. This is exactly what young women guard against every day. For succulents, this wavelength band of light can promote epidermal cell aging, making the outer shell hard and thick, so it does not look so tender, but at the same time the plant's resistance increases, and its resistance to external physical damage greatly increases. Especially for those whose homes are in communities with a good environment, plants placed outside can greatly improve resistance and survival rate under the ravages of wild birds, squirrels, and other creatures. More importantly, plants with moderately aged epidermis can avoid sunburn under suddenly intensified sunlight. Therefore, giving appropriate and moderate UVA training is something home cultivation must pay attention to.
UVB, wavelength 275-320 nm, also called medium-wave erythema effect ultraviolet, with medium penetrating power. Only about 2% can reach the ground after passing through the atmosphere. This wavelength band of ultraviolet light can help animals with mineral metabolism and vitamin D formation. When we bask in the sun, we are actually basking in UVB, so old Jiang likes to call it the ray of life. For plants, UVB is part of promoting photosynthesis, except that its promoting effect is the opposite. In appearance, it can dwarf plants, thereby allowing nutrients to accumulate in large amounts in the plant's roots and stems. The ultimate purpose is to improve the plant's constitution through nutrient accumulation and promote flowering and fruiting. Without UVB, all plants in the world would become soft, floppy leek seedlings. (Lin Daiyu's physique, Yao Ming's height, everyone can use their imagination.) From the perspective of home cultivation of succulents, UVB irradiation can make plants dwarf and compact. In appearance this is more beautiful, and in substance it increases resistance. The long-nosed king mentioned earlier is a negative example.
UVC, with a wavelength of 200-275nm, is also known as short-wave germicidal ultraviolet. Its main function is sterilization; excessive exposure causes cells to die off en masse, which in humans means skin cancer and in plants means scorching and withering. I like to call it the extermination ray. Fortunately, though, it has the weakest penetrating power, unable to pass through most transparent glass and plastic, and most of it is absorbed by the ozone layer as it crosses the atmosphere (so protecting the ozone layer matters a lot...). For home cultivation of succulents, since the dosages used are generally small, appropriate UVC exposure is a must for plant health and sterilization needs. For one thing, it can kill harmful microbial populations on the plant surface or in the surrounding environment; for another, it can likewise promote epidermal cell metabolism, by the same principle as UVA.
Alright, that wraps up the invisible light. Old Jiang's years of accumulated effort has finally turned into black and white on the page. I feel great~
3. Plants' pursuit of light
So what characteristics define the pursuit of sunlight by South African succulents in a home environment? If you're smart enough, you should already have some sense of it after reading the "physiological characteristics" and "sunlight" sections above. If you still don't, that doesn't mean you're slow, only that you're more studious. Since you love learning so much, keep listening to me ramble.
In a home environment, as mentioned earlier, there's shading, so for most of the time there's no direct light. And because objects like awnings and windows intercept it, even the light that does come in lacks enough invisible light (such as UVB, which loses over 80% when filtered through single-layer glass, mainly due to the lead element in ordinary glass). At the same time, too much deliberately intensified light causes excess UBA and UVC, so once-plump plants either get sunburned or turn old and stiff. It's fair to say that the environment for home succulent cultivation is a pathological one, an environment deficient from the start. This has nothing to do with how much fertilizer you use or how much water you give; it's innate. Unless you're willing to knock out your ceiling, though I reckon your upstairs neighbor wouldn't agree to that.
Such an innately deficient environment causes many adverse consequences, such as: leggy growth, reduced resistance, fungal outbreaks, bacterial spread, or else sunburn, death by sun, being baked like a dried corpse... When we grow flowers day to day, we often hear people say that flowers must be grown in the open air, that indoor-grown ones won't thrive, that you can raise people but not flowers, and so on. Though these sayings come from ordinary folk, on closer study they all actually have scientific basis. The key issue is precisely this word "light."
In fact, it's not that there's no solution. Besides smashing the ceiling, there are many other ways to correct or compensate for the disadvantages of insufficient light. For example: chemicals, water control, lighting methods, increasing the temperature differential, treating things differently by season, and so on. "Chemicals" are not my specialty and must be set aside. As for "water control," I've classified that under the "water" chapter, so I won't discuss it now either. In this chapter, let's first talk about the other two methods.
(1) Tips for balcony growers to make effective use of sunlight
Most apartment-dwelling balcony growers should have a balcony (I admit that's a pointless remark, since without a balcony what would you grow flowers on). Most balconies are enclosed. An enclosed balcony has decent lighting conditions, but as I said earlier, glass blocks ultraviolet, so I suggest keeping the windows open for as long as possible, within whatever you can control. This is a very good method, especially for Aizoaceae plants; under full-spectrum scattered light, they do far better than under direct light with a missing spectrum. I once ran an experiment at home: Lithops (living stones) grown under unobstructed scattered light on the balcony, compared with Lithops of the same age, size and variety sunned behind glass on a bedroom bay window. The former were noticeably shorter, fatter and sturdier, and their epidermis aged in a very pleasant way, not at all as plump as the latter. They even showed no obvious dormancy in summer. After repotting, the difference was even clearer: the former had distinct, thick main roots that were not very lignified, with well-developed lateral and fine roots, and came up with a big clump of soil attached, while the latter were much weaker, healthy enough but clearly hothouse children that couldn't take wind and rain.
If you grow Haworthia, there's another thing to note: if the balcony has windows on three sides, place the Haworthia in the east position, and along the west window put sufficiently tall green plants or hang shade netting. If the balcony has windows only on the south side, then place them in the west position. There's only one reason: Haworthia needs moderate-intensity short-day light, and the early morning sun that first reaches into the balcony fits that requirement exactly. As for shading, if your balcony has an awning, you needn't worry about it at all. That's because the sun's angle differs with every season; the closer to summer, the more overhead the angle, and when midday shading is needed, sunlight often doesn't reach into the balcony at all. If you like your summer plants plump too, a single layer of netting with 50% shading is enough. If the plants are still shriveled despite the shading, then congratulations, because you get to repot and play in the dirt again.
(2) Choosing lighting by season
Given that South African succulents are all winter-growing types, home cultivation must make full use of the growing seasons. Because the southern climate has four distinct seasons, and neither the low winter temperatures nor the high summer temperatures can be withstood by Haworthia or even Aizoaceae, most people's plants are dormant in these two seasons. The difference is that Haworthia is in shallow dormancy in winter and deep dormancy in summer, while Aizoaceae is exactly the opposite. A few better-equipped growers use heating or homemade evaporative cooling pads and other methods to artificially regulate temperature so the plants keep growing. But I believe most growers, like me, can only let it be and let the plants go dormant naturally. (The very few who keep giving heavy water and fertilizer in summer or winter, afraid the plants aren't eating enough, are outside the scope of this discussion.) That being so, plants only grow in spring and summer. From what I've observed in Hangzhou's climate, the main growth peaks are generally early October to the end of December, and early April to the end of June.
How efficiently you use these few months determines how fast your plants grow. Some people often envy how quickly others' plants grow, but in fact the other person's conditions are much the same as yours. The difference is that they made good use of these months, while your plants spent these months putting all their energy into rooting.
To make good use of this period, giving the plants plenty of natural light is essential. Take Haworthia as an example: in spring, after a winter of continuous rain and low temperatures, the plants in shallow dormancy have accumulated quite a few toxins, and bacteria and insect eggs in the potting soil begin to stir. At this time you need to gradually increase light, and the windows that haven't been opened for months should be opened too. On one hand, the natural warming of the potting soil in sunlight can wake the plants into secreting growth hormones; on the other, the ultraviolet in sunlight can kill potentially harmful bacteria and insect eggs in the soil. But note: never expose them to sudden full sun. As said earlier, before the epidermal cells have had time to age, the UVA and UVB in sunlight are fatal to plants. The same goes for autumn. Besides paying attention to light intensity and how well the plants have adapted, on clear, crisp autumn days you must watch the plants' condition at all times, because in the south the ultraviolet intensity in autumn far exceeds that in summer. Generally, autumn light levels should be such that the leaves no longer stay tender green; if the leaves turn reddish, that means the light is too strong, and for plants just waking from summer dormancy you need to increase the shading.
The leggy growth we discussed earlier does not include the temporary spreading or stretching caused by rapid growth in spring and autumn. The best time to control leggy growth is not at the peak of growth, but in the period before dormancy, namely the end of December and the end of June in the south. That's because during that period the day-night temperature difference is large and the plants have just entered their nutrient accumulation phase; appropriately increasing light during this time helps make the plants more compact and tighter. It also speeds up nutrient accumulation, which both controls (or rather corrects) leggy growth and aids the physiological preparations before dormancy.
The above is a lighting plan that, on the premise of ensuring the fastest growth rate, preserves the plant's shape to the greatest extent. Plants grown this way may look a bit plumper, not strictly compact and squat. It may not suit growers who pursue extreme form, don't care about growth speed, and compete with their plants over lifespan, but for ordinary home hobbyists whose pleasure is keeping plants alive and healthy and occasionally snapping a few photos to post on forums for beginners to critique, it's already enough.

4. Water and succulents' pursuit of water
1. The place of water among the three essential elements of plant growth
The three essential elements of plant growth are sunlight, air and water. By rights water comes last, but for home cultivation of succulents, I think water control matters far more than the other two. Everyone should know from experience that too much or too little water supply causes poor growth or even rot and death. Especially in a home environment, because the plants' transpiration is low, it's easy to get the contradiction where after watering the soil won't dry, while if the interval between waterings is too long the soil dries out completely and becomes very hard to rewet. More often, the top of the potting soil is already bone dry while below it's still wet, and one careless overwatering brings root rot and leaf rot right after. Of course this also relates to soil structure, but in fact, as long as you control the water supply well, the soil mix ratio can be much more flexible. There's an old saying: watering takes three years of skill, and that's true. For home flower growing, watering technique is absolutely a key part, and for the special category of succulents, water control is all the more important.
2. Watering takes three years of skill
A while ago I had time to sum up this so-called "three years of skill." Likewise, I can't hold it in. How much I write is Old Jiang's business; whether you read it is up to you.
The beginning of "three years of skill" is the entry stage. The first thing you need to understand is "water nature." Some student says, "My water skills are great, 100 meters in 10.3 seconds, I can hold my breath for 8 minutes..." The Hangzhou swimming pool is recruiting lifeguards, please hurry over there and don't let your talent go to waste listening to Old Jiang's nonsense here...
(1) Water nature
Water comes in several kinds. Classified by form of existence, it can be divided into surface water and rootless water. Surface water is all the liquid water in rivers, lakes and seas. Rootless water can be liquid water naturally condensed in the atmosphere, such as rain and snow, or water vapor existing in gaseous form, which is what we call air humidity.
Theoretically, surface water, having dissolved quite a few surface minerals and trace elements, has relatively high hardness, and after H2O evaporates it deposits a large amount of precipitated inorganic salts. This is what we usually call limescale. Rootless water is the product of surface water evaporating and then condensing again upon cooling. Since it already shed a large amount of precipitated salts before evaporating, it's also called soft water. Although it also contains trace impurities (a water droplet needs dust in the air as a nucleus to condense), compared with surface water flowing everywhere, the amount is negligible.
As said earlier, the succulent roots of succulents have very low osmotic pressure, and excess salts can cause root cell dehydration, so we say that compared with surface water, rootless water is more suitable for watering succulents. Some high-tech folks have analyzed the difference between surface water and rootless water in terms of molecular chain structure too, and written articles even more long-winded than this hefty piece by Old Jiang to argue it. I thought of quoting a few passages, but feared the readers would nod off, so I gave it up.
In addition, the pH of water is also an important indicator affecting water nature. Everyone knows about pH. Why is "Nongfu Spring is a bit sweet"? Because it's weakly alkaline. Animal cell fluid is weakly alkaline; only the body fluids of dying animals turn acidic, so people should drink weakly alkaline water. Plants are the opposite: most plants need acidic water. This isn't to say plants like drinking sour water, but because the waste excreted by plant root metabolism piles up around the roots and harms plant health. These excreta, plus the elements in the soil that plants can use but must first be dissolved, all of these need acidic water to dissolve. If the soil in a flowerpot is watered with alkaline water over the long term, the end result is that all of the above cements together and finally becomes the cornerstone of that flower's grave. Another student says, "My family waters flowers with Nongfu Spring, so why are they fine?" That's because... because this spring water isn't alkaline enough...
Alright, the previous few paragraphs are just a piece of knowledge; it's enough for everyone to understand. When it comes to actually doing it, I know you'll still go use tap water. Actually, tap water in the south is generally acidic; it's just that it has a bit more dissolved matter in it. It's fine for watering flowers. Before use, put it in a basin overnight, first to let the chlorine dissipate and second to bring the water temperature close to room temperature. When you have time, let the plants get some rain, and that'll do.
(2) Watering strategy
Thanks again to everyone for listening to Jiang someone ramble here. Since you've read this far, it shows you still have enough patience to keep going. Light a cigarette if you smoke, have some tea if you drink it, there's a lot more to come~
There's no fixed formula for growing flowers; every household has its own way, and I reckon nobody concedes to anyone else either. Every time Old Jiang visits fellow flower growers, he goes in all cultured and comes back swearing... Likewise, there's no fixed formula for watering. Some like dry growing - dry growing favors reproductive growth, enabling better accumulation of dry matter, but the plants may not be so plump. Others like wet growing - wet growing aids vegetative growth, with lush branches and leaves, but resistance may be poorer. So there you have it, pros and cons laid out before you; how you want to grow them is your own choice.
Of course, whether you prefer dry or wet, the timing of watering still has to be grasped. As for the word "timing," I believe all the masters agree on its existence. For succulents, the method of "water when bone dry" seems to have become consensus. Indeed, this method is the safest one, and many growers who manage to keep plants alive for 3 years rely on it to barely get by. But think carefully, if everyone knows "water when bone dry," then where does the saying "watering takes three years of skill" come from? Could it be that the ancients were all dim-witted and summed up only this foolish method of "water when bone dry" over five thousand years?
The answer is of course no. "Water when bone dry" is just a pet phrase of many experts in flower magazines. These experts fear others will master the core technique and snatch their rice bowl in the future, yet they're unwilling to toil away in obscurity as humble gardeners, so they came up with this catch-all phrase to hoodwink everyone. Unfortunately, Old Jiang has always been envious and foul-mouthed, and since childhood couldn't stand people with lower IQ and bigger airs than him, so I'm going to expose them...
"Water when bone dry" - what does "dry" mean? One day or 1 month? Think carefully and you'll know: this term is just a prop for sophistry. Plants, even succulents, suffer damage to the relevant cell tissues when their roots dehydrate. The Populus euphratica in the desert is about as drought-tolerant as it gets, growing wild and sprawling even where it hasn't rained for 30 years. But you may not know, based on what Old Jiang saw and heard during the years working and living in **: no matter how many years a place has gone without rain, wherever Populus euphratica grows, dig down along the roots and the soil within 5 meters is guaranteed to be wet; the groundwater may connect to oases hundreds of kilometers away. Do you think plants are stupid? They're very clever~
Wake up! Do you have groundwater in your pots at home? Since there's no groundwater, then you go give them "bone dry"? That they can barely stay alive is already being very kind to your RMB. Home isn't a greenhouse after all. A greenhouse has ground warmth and humidity; even after half a year of dryness, the air humidity is enough for undemanding succulents to get by, plus temperature differences and such (to be covered later). The so-called "water thoroughly when bone dry" is a completely different concept. Precisely because of this, watering strategy in a home environment needs to be specially planned.
As we said earlier, Haworthia wants moisture and Aizoaceae wants dryness. Whether moist or dry, maintaining appropriate water for home-grown succulents is essential. If we could repot and look at the soil to explain, then for Haworthia, when the soil down to 3 cm below the surface has turned dry and whitish, and the particles below still have moisture but won't stick together, you can water. For Aizoaceae, when the bottom 1-2 cm of soil (not counting the drainage layer) still has dampness, you can also water. These two watering timings keep the root hairs on the fine roots from dying of dryness to the greatest extent, on the premise of not causing physiological disorders from too much water. The plant's root hairs then needn't be forever in a cycle of dying - reviving - dying again, limited nutrients can be accumulated to the greatest extent, and the plants naturally grow better and better.
Speaking of "timing," of course we'll also talk about grasping "timing." We can't repot to look every time we water. Besides needing to practice feel and eyesight as basic skills day to day, there are naturally tricks~
Trick 1 - the weighing method. First settle on your own soil mix, and each time you pot up use the same formula as much as possible. At the same time prepare an empty pot, fill it with bone-dry soil, then weigh it; record the weight, then water thoroughly and weigh again; record the two figures. Next, weigh once a day. Besides checking how well your mix retains water, the ultimate goal is to see how many days it takes to return to the weight of the dry-soil pot. Subtract 1-2 days from that number of days, and that's your watering interval. The above is for Haworthia; for Aizoaceae you needn't subtract days. Of course, this method ignores the roots' water uptake and transpiration; generally potting soil with plants growing in it dries faster, so if the above data can be compared over the same period with the weight of a pot containing a plant, the watering interval you get will be even more precise.
Trick 2 - the medium color-change method. Increase the proportion of akadama in the mix, because akadama granules absorb water and transmit moisture quite well, and they change color with just a bit of water, making wet and dry very intuitive. A higher proportion of akadama in the mix strengthens moisture transmission within the potting soil: the top dries quickly while moisture below keeps being transmitted up, until the moisture content in the lower medium drops to a critical point, and that critical point is often the start of the watering signal. I suggest raising the akadama proportion in the mix to above 40%, and top-dressing the pot surface with pure akadama of 2-3 grain size. When the akadama on the surface turns pale yellow and whitish, Haworthia can wait at most 1 more day, and Aizoaceae should be watered in 2 days. Of course, this is data from my own mix; if you want to use this method to set your watering interval, you still need to adjust it to your own mix. If you can't be bothered to adjust, then keep slowly reading Old Jiang's rambling; I'll introduce my own medium formula later.
Tricks that should be spurned
1. The toothpick method. Many people like to use this, but in practice it easily stabs and damages the roots growing along the pot wall, and once you water, rot is guaranteed. Spurn rating: 3 stars.
2. The finger-probe method. I once saw this method in a translated article by someone else. I don't know if anyone actually does it. I think this method is very stupid. Never mind that everyone now likes to use granular soil so the finger can't go in at all; even if it goes in, the finger gets filthy, the nice top-dressing soil on the pot surface is messed up, and worse, some precious fine roots floating on the pot surface may get snapped off. It can be said that this is a completely stupid method with a hundred harms and not a single benefit. Spurn rating: 4 stars.
3. The tap-the-pot-and-listen method. I won't criticize this one anymore; it's utterly unreliable. Unless everyone has trained their hearing to that of a musician like Lang Lang, this method is no better than sticking your finger straight in. Spurn rating: 5 stars.

5. Selection and application of growing media
Growing medium refers to the medium in which the roots of potted flowers grow; its main functions are to anchor the plant and provide nutrients. This medium isn't just soil; it also includes various organic and inorganic soilless growing media, common ones such as: bark, peat, vermiculite, expanded clay pellets, orchid stone, etc., and more unusual ones such as: coal slag, rock wool, polyester foam granules, rotten cotton, etc. Of course it also includes hydroponics and air culture.
In short, theoretically speaking, any material that can keep its physical structure from easily changing during wetting and root growth, won't undergo drastic chemical changes, can absorb and slowly release water and nutrients, and has a moderate particle size can be used as a growing medium.
But this is only theory. In most cases, plants can only grow in media suited to themselves. The "suited" mentioned here includes many factors, the main ones being pH, soil salt content (EC), medium composition, organic matter content, degree of decomposition, particle size, etc. In addition, a single medium, because it can't provide comprehensive nutrients, or because some component is overly concentrated, is also unsuitable for growing plants. (Hydroponics is not discussed here; in fact hydroponics also needs rich nutrients supplied from outside for plants to grow.)
Here I need to promote a concept - the root-affinity of a medium. The root-affinity of a medium should actually be called the roots' selectivity toward the medium. Simply put: whatever objects the plant's root hairs like to cling to, those objects have strong root-affinity. This characteristic is determined by the medium's chemical properties, physical form and particle size. Generally, media with smaller particles, lower hardness, looser texture and a more acidic nature have stronger root-affinity. Root-affinity is very important; it shows that all the properties of this medium are very suitable for plants. The root hairs on the roots can grow and absorb water and nutrients on it over the long term. Of course, it's not that other media with poor root-affinity have no root hairs attached, because the roots' selection of medium isn't foreseen in advance but corrected afterward, so root hairs will also try to grow on media with poor root-affinity, but their lifespan will be very short, invisibly increasing the plant's consumption and wasting energy. Over time, the gap in plant growth becomes large. When we repot, we see that some plants' roots are very clean, with thick and fine roots all smooth. Other plants' roots are very dirty, covered with medium from top to bottom. If you observe carefully, you'll find the latter have more developed root hairs and the upper part is often healthier. And the media used by these two pots of plants showing this phenomenon are often not the same. This demonstrates the existence of medium root-affinity.
I won't introduce the theory much more; if this thing got going, it couldn't be wrapped up without hundreds of thousands of words. Let's talk about the practical side instead.
1. Introduction to various growing media:
(1) Akadama
For home succulent cultivation, the best is of course to imitate the soil of the native habitat. The company Old Jiang is at has a project department in Africa near the south, so Old Jiang once asked local colleagues to help study the wild soil. Overall, Africa's local soil is mainly sandy, with sand and gravel content around 80%, and the soil surface under some tree shade and grass clumps is covered with a thin layer of humus. The soil's water content is extremely low; over vast areas you can dig down 1 meter without seeing a trace of moisture, but in areas covered by shrubs, below 30 cm it's slightly damp. From the above analysis, the native soil composition is roughly coarse sand + leaf mold + gravel. It should be said that such soil isn't hard for the vast majority of succulent enthusiasts to obtain, and enthusiasts in Europe and America do indeed use such media to grow succulents, with good results. But for home cultivation, such a mix is too heavy, and for enthusiasts growing large quantities on balconies or flower racks, it's not quite suitable. It's also a bit coarse-looking, not fitting most readers' tastes (most readers who like succulents have a cleanliness obsession, don't they? Don't they?)
So the petit-bourgeois crowd represented by the Japanese developed growing soils based mainly on volcanic ash such as akadama and kanuma. Besides meeting the needs of most domestic enthusiasts, this also contributed several percentage points to the island nation's economy. These two representative soil-mix materials are indeed quite conventional; their composition can theoretically satisfy plants' requirements for a medium to the greatest extent. The history of Japanese use of akadama can be traced back 20 years by verifiable evidence. Back when "Chibi Maruko-chan" was a hit, one episode showed Maruko's grandpa sifting akadama there; I reckon that counts as product placement of that era.
Besides succulents, the Japanese also use akadama extensively in growing other plants. And based on different origins they developed products suited to different uses. Old Jiang isn't helping advertise akadama. Japan is a major horticultural country, but its land area is small and resources scarce, so making full use of its own volcanic conditions is also a move of necessity. The poor naturally have the poor's way of living, so they go dig some volcanic ash at the foot of Mount Fuji, pick up some rotten leaves under the crooked tree in the backyard, mix it all up and use it to grow flowers. Unexpectedly the results were pretty good, so this scarce resource was continuously developed, studied and systematized, marketized, and over decades of accumulation formed a very sound industrial chain. Scaled, corporatized things naturally have enough competitiveness, so Sichuan's Sendai soil got outdone, and the Northeast's peat got outdone too... Back to the point, I'm not blindly worshipping Japanese goods; what I worship is the system. Things under a system are generally more stable than things dug up haphazardly by small workshops.
Akadama's greatest advantages are low fertility, slight acidity, aeration and water retention. These 4 items have already met the physiological needs of most plants, and for the physiological characteristics of succulents, it's almost a perfect match. Ordinary beginner players growing succulents with akadama, without much guidance, can all grow them decently, so akadama can also be called "idiot-proof soil." Its characteristics greatly lowered the threshold for succulent cultivation, and with its price neither too high nor too low, akadama can be said to be an important factor promoting the rapid development of succulents in China.
What needs special attention here is that not all akadama is suitable for succulent cultivation. As said earlier, different origins, different functions. For succulents, among the akadama sold domestically, the brand "Longquan" is the most suitable. Many readers like to use "Nihon Line," but "Nihon Line" emphasizes being hard and not powdering. Its texture is high-temperature-sintered heavy clay, with relatively poor aeration. Once it powders, the soil structure in the pot is greatly destroyed. And because its texture is hard, its root-affinity is also poor. It's barely okay for growing Cymbidium orchids, herbaceous flowers and conifers, but for succulents it's not so suitable. "Longquan"'s texture is sandy soil; although its granule cohesion is poor and it crumbles easily, its texture determines that even if it all crumbles it's still sandy loam. Its basic functions won't all be lost. And "Longquan" isn't a sintered soil like "Nihon Line," so its internal organic matter content is relatively high, and its soil composition is close to native soil. (Don't ask Old Jiang why he knows so much. Back then, when I tirelessly pestered one master after another asking what akadama they used, I was laughed at countless times, so the masters I questioned can testify that this conclusion isn't fabricated by Old Jiang.)
Of course, besides akadama, other materials aren't without merit. On the contrary, many materials, though not very comprehensive in function, greatly exceed the conventional akadama in certain characteristics. For example:
(2) Peat
Peat is formed from the bodies of shrubs and mosses decomposed and piled up over thousands of years. That evolved from swamp plants is low-moor peat, with high water content, severe decomposition, high humus content, but very high EC value and low pH; Northeast black peat is a representative of this. That evolved from moss and lichen in plateaus and some plains is high-moor peat; because it's long been in a dry environment and often exposed to sun and rain, its decomposition degree is lower and humus content lower, but its EC value is also very low and pH slightly low, with imported FFD peat as the representative. For plants, low decomposition, high humus, low EC and slightly acidic pH is the best choice, so the two peats above each have their strengths in terms of characteristics. But overall, for growing succulents, high-moor peat is more advantageous.
We habitually use peat as the medium in the mix that provides organic matter. Adding an appropriate amount to an all-granular medium can also loosen the soil and strengthen the soil's buffering capacity for fertilizer and water. In addition, because of its fibrous structure, it can create a microenvironment suitable for plant root hair growth, with special effectiveness for rooting and revitalizing seedlings and weak plants.
(3) Orchid stone
What's generally considered orchid stone should be a volcanic ash product, that is, pumice, foot-scrubber stone and the like, high-temperature foamed ore. But there are also synthetic substitutes, such as Tangji orchid stone, Hyuga stone, etc. Since their properties are much the same, I won't describe them separately; this article calls them all orchid stone.
Because orchid stone is harder in texture than soil and much weaker at retaining water after absorbing it, it can be considered a hydrophobic material. Although its internal pores can store water briefly, they can't reach the level of producing "capillary action," so it dehydrates very quickly. But its pores can reduce soil density and achieve a loosening effect. Natural volcanic-ash orchid stone should be acidic in pH, but Old Jiang's tests show synthetic ones are weakly alkaline, so they must be treated differently in use.
Because orchid stone has a lower degree of water saturation than soil, adding orchid stone to the mix can lower the potting soil's overall water saturation and relatively increase the oxygen content of the soil. This isn't what we usually think of as "aeration"; stones don't breathe. The so-called aeration is only an indirectly achieved effect.
Orchid stone has no fertility. Its EC value varies considerably depending on origin or source. It's generally believed that synthetic ones have slightly higher EC values, so in practice natural materials should be chosen first.
(4) Bark
There are 2 common types of bark usable as horticultural material. One is pine bark (the lumps on the outside of pine bark). Pine bark is fairly expensive and its decomposition degree is very low, so it's generally used as horticultural mulch and not very suitable as a growing medium. The other is the decomposed bark of deciduous trees. This bark mostly comes from natural decomposition layers in the deciduous forests of the hilly areas of the Central Plains region. A suitable decomposition degree is 3-5 years. Compared with peat, its structure is more stable and less prone to being compressed and deformed into soil compaction, and bark's ability to slowly release organic matter is better, so it's quite a good material.
Bark's only drawback is that it easily has impurities mixed in. Since it's mostly harvested naturally, it inevitably contains insect eggs, grass seeds and other incompletely decomposed organic matter, which easily leads to an overabundance of organisms in the pot after planting. In plain terms: pests and stray microbes will breed. So bark needs screening, sun exposure or high-temperature treatment before use, and this is also a major defect restricting its use in a home environment.
(5) Vermiculite
Vermiculite is the high-temperature expanded product of mica rock. Compared with the original ore, it's like the difference between popcorn and rice. Vermiculite's density is extremely low and its internal voids are very large, so it's generally used in industry as insulation material. In horticulture it's used as a soil-loosening amendment that drains quickly, stores water and releases it slowly.
Vermiculite's water saturation is very high; vermiculite of unit weight can absorb 4 times its own weight in water. Moreover, although vermiculite holds water very well, its water conductivity is quite strong. In other words, after adding vermiculite to potting soil and watering thoroughly, the difference in drying speed between the top and bottom of the soil layer is relatively small, which makes it easier for the grower to judge the moisture inside the pot by observing the wetness of the soil surface, thus reducing the difficulty of management.
Although vermiculite is an inorganic ore, its own unique ion exchange capacity gives it activity. The specific knowledge is profound, so I won't elaborate here. Everyone just needs to know that active vermiculite can promote plant root growth, and mainly the growth of clustered roots. What needs explaining here: in general articles introducing flower cuttings and rooting, people are advised to use vermiculite as the medium. The reasoning given is merely that vermiculite contains no nutrients and is fairly sterile, etc., but the real reason is actually to make use of vermiculite's ion exchange capacity.
But vermiculite also has a fatal drawback: it's fragile. Over time it turns to powder and sticks together, ultimately destroying the soil structure and compacting the soil. So vermiculite can only be used as a temporary medium for revitalizing seedlings and weak plants or for rooting cuttings, and isn't very suitable for large plants.
(6) Perlite
It's also a hydrophobic, breathable material. Apart from being cheap, it has no other advantages. It can replace orchid stone in large-scale planting to save costs. But for home growing, it's not recommended. First, because it's too light, it flies everywhere when you water, which is extremely unsightly. Second, this material produces a great deal of dust and may contain heavy metal components, so from the standpoint of environmental protection and human health, it doesn't meet requirements.
2. Application of growing media
From the above, a sharp-eyed person can see that Old Jiang still leans toward akadama. Indeed, up to now, after taking quite a few detours, I think akadama is still the best to use. I don't pursue any special effects; as long as the plants are healthy, even if the shape isn't so standard, it doesn't matter. So the conventional akadama is undoubtedly the first choice.
Of course, even the best thing needs skill in use. Compared with the Japanese using large proportions of materials like akadama and kanuma, domestically there's more inclination toward mixed ratios. Ordinary players pair materials like pumice, peat and orchid stone, mainly of course to make the soil composition as rich as possible to meet the plants' growth needs, and second, some advanced players have also seen akadama's shortcomings and use ratios to enhance strengths and avoid weaknesses. They take the differing characteristics of various materials to meet their own different needs.
For the succulents we focus on, there are 2 systems for making the soil mix: one is the fleshy-rooted plants represented by Haworthia, and the other is the semi-lignified fibrous-rooted plants represented by Lithops.
(1) Soil mix for Haworthia plants
Haworthia plants, as we said earlier, have thick, succulent fleshy root clusters, and their requirement for soil is aeration over water retention. In the mix, you need to make great use of the soil's aeration capacity, mixing as much as possible a growing medium that allows air circulation while retaining moisture and fertility. But you also need to consider the potting soil's overall support capacity for the plant.
Knowing akadama's characteristics, the main material in the formula is of course akadama, but akadama's nutrients aren't complete, and using it in large proportion creates nutrient deficiencies for the plants. And fertilizer for home cultivation is hard to master, so we need to add nutrients to the soil in advance. Here I suggest using peat for the nutrients, and preferably granular peat derived from Northeast peat. This increases soil nutrients while maintaining the soil's granular structure and aeration.
Of course, for experienced hands with mature technique, fibrous peat can produce even more unexpected effects, because as said earlier, a fibrous structure can create a root microenvironment and increase the contact area between roots and soil. So for readers who can properly control moisture, using fibrous peat rather than granular peat is more conducive to root hair attachment and growth, thus greatly increasing plant growth speed. For the slow-growing Haworthia plants, increasing growth speed also means sooner displaying the plant's qualities, sooner flowering and fruiting, and propagating the next generation.
Next is the addition of hydrophobic materials. Although akadama has a granular structure, with lots of gaps between granules to drain excess water, the granules themselves hold a lot of water, and akadama will also crack apart over time under the action of roots, so structurally more stable orchid stone is still needed to strengthen and maintain the potting soil's drainage capacity and lower the average water content. Orchid stone is the regulator in the mix; by increasing or decreasing orchid stone you can make a medium suited to different plants.
The above 3 components are respectively defined as: main soil, nutrient additive, water content control material. Particle size 3-6mm; for fibrous peat, use a 1mm sieve to sift out the powder before use. These 3 in ratio can meet most of the plants' needs. As for other materials, you can add them as appropriate according to personal preference. For example, if you like richer colors you can add some red volcanic stone or Kanuma soil. Those needing vigorous roots can add vermiculite. Those growing Lithops can add some charred charcoal (this thing can actually only regulate soil pH, so it's useless in Haworthia cultivation, unless it's semi-carbonized, which can provide a little organic matter), and so on.
Here are a few mixes I'm personally using and quite satisfied with:
Akadama : orchid stone : granular peat = 5:3:2. Particle size 3-6mm, suitable for deep pots and varieties with thick, large roots, such as Haworthia maughanii and Haworthia truncata.
Akadama : orchid stone : fibrous peat = 4:4:2. Particle size 3-6mm, suitable for shallow pots, varieties whose roots aren't so thick, or half-grown seedlings still developing.
Fine akadama : vermiculite : fine orchid stone = 1:1:1. Particle size 1-3mm, suitable for leaf cuttings rooting and seedling cultivation. Note the vermiculite in the mix; please review the earlier knowledge about ion exchange and root-affinity.
(2) Soil mix for Aizoaceae
Aizoaceae plants are mostly semi-lignified fibrous-rooted, and because this type of plant has dormancy characteristics and needs the potting soil kept dry during a certain period, the key to the mix is meeting both the compact environment the fibrous roots need and the requirement of drying quickly.
Compactness and quick drying - these two concepts look contradictory, but in fact, analyzing the native soil, these two characteristics exist simultaneously. It's precisely the native sandy soil having the above 2 coexisting characteristics that ensures the plants' growth. Enthusiasts in Europe and America also like to use similar sandy soil to grow Aizoaceae, with good results. But as we said earlier, in a home environment it's best to use other things as substitutes, to avoid excessive soil density making the potting soil overweight and affecting the scale of cultivation.
Akadama and kanuma should still form the base. Here you need 1-3 mm granules of akadama and kanuma, and for nutritional reasons fibrous peat must also be added. This way you can roughly mix a synthetic soil similar to what is used for Haworthia cultivation, but this only satisfies the requirement of density; the requirement of fast drying has still not been taken into account. So we need to add an appropriate amount of vermiculite to the above ratio. As mentioned earlier, vermiculite has a strong effect of promoting vigorous root clusters and has good water conduction capacity. The former is greatly beneficial for fibrous-rooted plants, while the latter allows water in the lower part of the pot to be conducted promptly to the surface and evaporate quickly, which precisely addresses the requirement of fast-drying potting soil. And the practice of repotting mesembs once a year compensates for vermiculite's drawback of easily crumbling and compacting. In addition, vermiculite can also greatly reduce the density of potting soil and lighten its weight, fundamentally distinguishing home-mixed soil from native habitat soil. This highlights the advantages of home-mixed soil.
Here is my own soil mix ratio for growing mesembs:
Akadama : kanuma : fibrous peat : vermiculite = 1:1:1:1, plus a little smoked charcoal. Granule size 1-3 mm is suitable for Lithops and Conophytum over 2 years old and mature plants.
Akadama : vermiculite : fibrous peat = 1:1:1. Granule size around 1 mm, suitable for seedlings within 2 years.
Vermiculite powder : fibrous peat powder = 1:2, suitable for sowing.
Regarding substrate ratios, many publications emphasize adapting to local conditions and adjusting the ratio according to one's own care habits. But Lao Jiang suggests: it should be the other way around - adjust your care habits according to the substrate ratio. Because substrate ratios are not arbitrary; on the contrary, they should be very rigorous and unique, adjustable at most according to the latitude of your location. Lao Jiang believes there exists a single "formula" for soil mixing, it's just that no one has summarized it yet.
3. Recycling and reuse of substrates
Due to the limitations of home cultivation, even the best-mixed substrate has a service life. From the long-term flushing of irrigation water, the original granular structure of the substrate is destroyed by the massive loss of organic matter. The substrate gradually pulverizes and compacts. Compared with soil in nature, which renews itself through air, fallen leaves, and the decay of dead organisms, potting soil in home cultivation needs to be renewed by human effort.
But in the substrate that has been replaced, many materials still retain their original shape (such as kanuma). Throwing it all away is clearly not in keeping with the spirit of environmental protection and thrift. So, for this soil that is more expensive than rice, many growers choose to recycle and reuse it.
Making full use of things is certainly a good thing, but you all probably know the dangers of old soil - you're just choosing to forget selectively... Today you're out of luck, because you've run into Lao Jiang who loves digging into the soles of your feet, and here I'm going to help you remember.
First, old soil contains large amounts of acidic substances. You probably know that these acidic substances are products of plant metabolism during growth. Some textbooks even say this is a form of self-protection by plant roots to neutralize soil alkalinity. In short, this acidic substance is not simply "acidic", otherwise acidic soil would be even more suitable for plant growth, and why would there be any need for soil replacement? Humic acid in soil and the acid excreted through metabolism are two different things - the former is a nutrient, the latter is waste. Although both have a pH below 7, the latter's chemical composition is far more complex, and its impact on plant health is unknown.
Second is the accumulation of salts. During care, there will inevitably be times of fertilizing and spraying, and the water used for routine watering will more or less have salt precipitates. All of these eventually seep into the soil and accumulate. Although watering flushes out a little, the water poured in simultaneously brings in new salts. So the salt in the potting soil only increases.
Third is dead leaves and rotted roots. In nature these two things are green compost, but in a flowerpot they become a breeding ground for bacteria. Sometimes when we repot (especially deep pots) we see patches of mycelial fuzz growing in the potting soil, in colors like yellow and blue-green - this is bacteria thriving after the plant's own roots have rotted. Succulents are not like herbaceous flowers; their roots do not secrete much antibacterial substance, and even a little stray bacteria can contaminate the potting soil - at best causing root rot and stalled growth, at worst infecting the whole plant. If your own rotted roots can do this, then just imagine the consequences of rotted roots of unknown vintage in old soil.
Finally there is the loss of nutrients. Old soil in a pot is subjected to long-term flushing from watering, and since succulent growers all like to make their soil very porous, compared with growing herbaceous flowers, the water flow through succulent potting soil is faster, and the corresponding loss of nutrients is more severe. Compared with new soil, old soil has far less water-soluble, plant-available effective components.
However, old soil has one advantage. Take akadama as an example. In pots that have been used for over a year, the parts that have not yet pulverized develop greatly increased internal pore space under long-term watering, making the granules more porous. From the perspective of physical air permeability and water permeability, almost no ready-made material can compare with such soil. This should count as a characteristic accumulated over time.
In view of the above, old soil must be properly treated before it can be used again. To address the above defects, Lao Jiang offers the following treatment plan for everyone to discuss.
(1) First sieve with a 2 mm mesh sieve. Because granular soil crumbles and pulverizes under the extension and pressure of plant roots, the soil around the roots is generally broken. Removing the fines below 2 mm is equivalent to removing the portion with the most root exudates.
(2) Pour in potassium permanganate solution and soak, to achieve disinfection and remove excess salts, and use the different densities of materials such as kanuma and akadama to separate them, facilitating subsequent differentiated treatment. While separating, pay attention to dead leaves and rotted roots floating on the water surface, and be sure to clean them out thoroughly.
(3) Scoop out and dry in the sun. If the mixed soil is not cleanly separated, after drying you can repeat the soaking-drying steps, but there is no need to use potassium permanganate - clean water is sufficient.
(4) After drying, kanuma can be directly mixed into new soil for use, with the ratio unchanged. The treated old akadama should be mixed with an equal volume of new akadama and half a volume of granular peat (ratio converted to 2:2:1), bagged for later use. During normal use, mix it in according to the akadama ratio described earlier (that is, treat this mixed soil as if it were all akadama, because old akadama is very porous but lacks nutrients, while granular peat has nutrients but is not porous - mixing them together exactly cancels out each other's shortcomings).

Six. The effect of temperature difference on succulents and its control
1. The effect of temperature difference on succulents
For succulents native to South Africa, the most suitable growing temperature for most varieties is between 12-28°C. This figure should also be the average high and low temperatures of the growing season in their native habitat.
In the Jiangnan region represented by Hangzhou, where Lao Jiang is located, because it lies in the zone where northern and southern air currents meet and struggle, it often happens that just as cold air leaves, the subtropical high takes over. Throughout the year, the days that can maintain 12-28°C are only in May, June, October, and November - about 4 months. Most other months are either too cold or too hot, so that often you go straight from a cotton-padded jacket to short sleeves, and after wearing short sleeves for two days you suddenly need a sweater again. (This is also why spring and autumn clothing sells poorly in Hangzhou.)
Such a climate is barely tolerable for people, but for plants, especially succulents, it is quite troublesome. Some people say that a large temperature difference can promote plant growth. That's right, the day-night temperature difference can indeed promote plant growth. But you may not have understood the principle behind this growth. So let me explain it to you slowly...
How well a plant grows depends on how many nutrients it accumulates within its body. During the day, plant photosynthesis is a process of producing nutrients. Within a reasonable upper temperature limit, the higher the temperature, the stronger the photosynthesis, and the more nutrients are produced. This process can be seen as a plus point for the plant's nutrient accumulation.
At night, since there is no light, most plants' physiological nutrient-producing activity stops, and the plus is zero. But the plant's transpiration continues. Transpiration is when a plant relies on ambient temperature to evaporate water from its leaves, and at the same time, the siphon effect brought by evaporation prompts the roots to absorb water. This process consumes nutrients from within the plant, and can be seen as a minus point for the plant's nutrient accumulation. The higher the ambient temperature, the greater the transpiration, and the greater the minus. So how many nutrients a plant can accumulate in a day depends on how much is produced during the day and how much is consumed at night.
Through the above explanation, I believe everyone should have an understanding now. The higher the daytime temperature, the more nutrients the plant produces; the lower the nighttime temperature, the fewer nutrients the plant consumes. This is where the effect of the day-night temperature difference manifests. Why are the grapes of ** so sweet they stick to your teeth? Why do the tomatoes of ** taste like persimmons? It's not because the guys there are hardworking - it's the climate of "wear a fur coat in the morning and gauze in the afternoon" that makes it so.
Alright, now that you know this principle, I believe no one will argue with Lao Jiang about the difference between the two concepts of day-based temperature differences caused by sudden warming or cooling, and day-night temperature differences.
In fact, sudden temperature rises and falls caused by climate have not only no benefit for plants, but extremely serious harmful effects. They not only disrupt the plant's normal physiological order, but also trigger various accidents. In terms of physiological order: for example, in spring, after the temperature has finally risen for a while, the plant begins to show signs of growth, and you have already happily started watering and fertilizing, busily enjoying yourself. Then suddenly the temperature drops, and the newly grown leaves immediately freeze in place. Never mind the consequences of the water you poured and the fertilizer you applied. Just this one frozen leaf could later trigger your urge to behead the plant. You say you won't behead it. Fine, don't. A few months later the frozen leaf starts growing - pointy on top, round on the bottom, the whole thing looks like a gourd... That's still the good scenario; if the whole plant had this shape you could at least pass it off as a new variety to fool yourself. The problem is that among a circle of good leaves there's just this one gourd leaf. Do you still behead or not? Then there are the accidents. After high temperatures, a sudden drop is actually fine - South African succulents have no problem with brief sub-zero temperatures. But after low temperatures, a sudden rise is troublesome. In the dead of winter, the temperature suddenly rises to 25°C, and a properly sealed greenhouse - the temperature suddenly shoots up to 50°C. Done for. When you get home at night, a whole greenhouse of steaming steamed pork awaits you to lift the lid... Besides these, there are pests, diseases, fungi, etc., all related to sudden temperature changes.
I think the summary of this section needs to be stated separately - temperature difference can promote succulent growth and nutrient accumulation, but it must be a controlled day-night temperature difference. Temperature differences caused by sudden weather changes are harmful and not beneficial to plants.
2. How to create and utilize temperature differences
The home cultivation environment means it's very hard for us to achieve the kind of perfect artificial temperature difference of a large greenhouse. (Greenhouses rely on the sealing effect of polyester film to store heat under sunlight, increasing daytime temperatures to widen the temperature difference.) But home has its advantages too. As long as you don't live in a pavilion, you can at least have warmth in winter and coolness in summer, and avoid extreme temperatures. So how to create a temperature difference requires working with the not-very-obvious temperature difference at home.
(1) How to create a temperature difference in winter
Although I said earlier that I still advocate letting nature take its course, minimizing fuss, and making the most of existing environmental facilities. But for the harsh winter in the south, letting nature take its course is equivalent to accepting nearly half a year of dormancy for succulents, especially Haworthia. This is unfair to the many southern growers. (Why do northerners get heating... The south has no coal but it has natural gas... Nobody's family is short of that little heating fee, right?) So the winter temperature difference should focus mainly on daytime heat retention.
Heat retention first requires sealing. Some growers in Shanghai have achieved considerable success using large storage boxes or building "pigeon cages" outside windowsills. I have a positive attitude toward both methods. Earlier when discussing water control I didn't advocate them, but when it comes to heat retention in winter, I think these two methods are still feasible.
But both methods have their own drawbacks. Storage boxes are too small in volume - for growers with larger cultivation scale, it's a drop in the bucket. Pigeon cages work during the day, but at night when the cold wind blows outside the windowsill, the internal temperature immediately drops close to the air temperature. Given Hangzhou's coldest winter temperature of -5°C, within a week the Haworthia leaves will all turn white and foggy, and then start rotting after spring begins. Unless you install heating wire and a thermostat - and these two things, anyone with an electrician's certificate wouldn't dare use. Why? Go get an electrician's certificate and you'll understand.
After all, the less fuss the better. Wrapping an existing plant stand is a more environmentally friendly approach. Common plant stands generally come in two types: wooden and metal. For wooden stands, I recommend wrapping directly with polycarbonate sheets (more attractive, and good insulation too). Except for the front and bottom, the other 4 sides can all be fixed with wood screws. The front can be made into a roll-up curtain using greenhouse film or soft glass, for easy opening. Under the stand you can place several saucers with a little water. First, this serves to increase humidity; second, the water can store daytime heat and release it slowly at night, preventing too rapid cooling at night when the sun isn't shining. Metal stands can be wrapped entirely with greenhouse film. To enhance insulation, you can use double or even 4 layers. Everything else is the same as for wooden stands.
A stand treated this way needs to be placed where it gets sunlight during the day. Generally, on a clear day with outdoor temperature around 5°C, the temperature inside the enclosure can rise to around 25°C. At night, no matter how low the outside temperature is, due to the double insulation effect of the home environment, the temperature inside the enclosure can be slightly higher than room temperature. (Any readers whose home room temperature is below 0°C? If so, raise your hand, and Lao Jiang will help organize donations of money and sweaters.)
The above methods are suitable for Haworthia and mesembs.
(2) How to create a temperature difference in summer
This topic is rather tragic. The sauna-like heat of the south gets in everywhere, and apart from air conditioning there seems to be no good solution. Never mind the daytime - the thing about frying eggs on manhole covers happens every day. At night it's slightly better; at least outdoors it can drop below 30°C. But indoors, a zero temperature difference of 30°C during the day and 30°C at night is very hard to change. You say there's air conditioning, but after all, few homes have central air conditioning. With split air conditioners, at night only the bedroom gets AC - you're not going to put your plants in the bedroom, are you? Some growers install small air conditioners in their plant rooms or even greenhouses. This is of course a good approach. But if everyone did that, what would Lao Jiang be rambling about for? After all, there are still more growers who prefer value for money...
We said that Haworthia is in deep dormancy in summer, which marks the end of the growing season. Compared with winter dormancy, summer dormancy is a physiological cycle behavior. Controlled dormancy allows the plant to accumulate the drive for growth in the next growing season, which is relatively beneficial for the plant. So in summer, the purpose of creating a temperature difference is not growth, but maintenance. Appropriately widening the temperature difference during summer dormancy can prevent physiological disorders caused by high temperatures. It can also use the relatively low nighttime temperature to dissipate heat accumulated in the potting soil during the day, thereby maintaining root health.
So the summer temperature difference should focus mainly on lowering nighttime temperature, letting daytime take its course. As long as you do good shading work, let it be whatever temperature it is. At night, without using air conditioning equipment, use physical cooling methods such as misting and electric fans. Misting needs to be done until the soil surface changes color and water droplets cover the plant surface, then turn on the electric fan. Water evaporation can carry away heat. The data Lao Jiang measured using this method is - in midsummer, after 8 PM, when the air temperature around the pots is 32°C, after misting and fanning, it can cool to 29°C within 1 hour. Then combined with opening windows for ventilation, or sharing air conditioning airflow from the room, the minimum nighttime temperature in the plant room can reach a level comparable to outdoor temperature (around 27°C). For Haworthia's summer dormancy, this low temperature is sufficient.
The above methods are only suitable for Haworthia. For mesembs, Lao Jiang recommends not withholding water in summer and growing them freely. As long as they are healthy plants over 2 years old, the more sun the better they look.
(3) How to create a temperature difference in other seasons
In winter, focus on daytime heat retention; in summer, focus on nighttime cooling. Then in the golden spring and autumn seasons, you need to focus on getting close to nature.
Getting close to nature means making the cultivation environment's temperature difference close to the outdoor temperature difference. In spring and autumn in the south, there is a natural large temperature difference of around 10-15°C outdoors, plus fresh outdoor air and natural dew moisture - it would really be a pity to waste it.
The methods here need no elaboration: open windows for natural ventilation, electric fans for forced ventilation, open-air growing, etc., etc. As long as you turn the plant room into a pavilion, the goal is achieved. Of course, beware of the late spring cold snaps and the return of the subtropical high mentioned earlier.
(4) Utilization of temperature differences
Once you've learned to create temperature differences, you can use them to regulate plant growth. The plump or compact specimen plants you see on Japanese websites are also the result of extensive use of temperature differences.
For succulents, the few weeks before the theoretical dormancy period are the reproductive growth stage. During this stage, apparent growth is very weak, but the rate of nutrient accumulation within the plant reaches its peak. And the timing differs for different families and genera - Haworthia shows it in early summer, mesembs show it in late autumn.
During this period, increasing the temperature difference can enhance the plant's nutrient accumulation. The plant becomes plump due to the increase in dry matter within its body, and the thickening of stems and leaves can correct the etiolation that accumulated during the growing season. Combined with the slow growth caused by low nighttime temperatures, the plant naturally takes on a short and plump appearance. Even sufficient temperature difference can offset etiolation caused by insufficient light - though Lao Jiang hasn't tested this, just mentioning it in passing.
Furthermore, temperature difference provides external conditions for flower bud differentiation. Plants adjusted by temperature difference will bloom more uniformly and vigorously in the subsequent flowering period, with sturdier flowers. This is very beneficial both for Haworthia hybridization and for viewing mesemb flowers. Just imagine a group planting of Lithops blooming all at once overnight - that feeling cannot be experienced without seeing it with your own eyes. (Readers who grow Lithops should choose group planting. Don't be so stingy with one pot per plant. Don't have that many? Leave a message for Lao Jiang, and Lao Jiang will give you --------------- seeds.)
Temperature difference is also very important for controlling the flowering period of Haworthia. I believe readers who have hybridization experience all know that a pairing you planned long in advance may fail because one of the plants just won't bloom in time, forcing you to give up. Fortunately, we still have temperature difference to use.
Increasing the temperature difference, especially raising the daytime high temperature, can promote flower bud differentiation in plants - this is an unchanging axiom that needs no proof. By controlling the daytime high temperature, you can control the flowering time of Haworthia. The higher the daytime temperature, the faster the flower bud differentiation; otherwise, the slower. Use this to adjust and synchronize the flowering times of plants for hybridization. For example: say you want to hybridize two Haworthia, one flower stalk is already 30 cm tall, and the other has just emerged. Then hurry - put the fast one on the windowsill and the other in the sealed greenhouse. Keep it sealed and sealed, and the flowering speeds will become the same...
However, for Haworthia species whose flowering periods are simply not in the same season, the temperature difference adjustment method may not work so well. Take Haworthia retusa types as an example: the earliest to bloom is 'Kangping', flowering in April, while the latest is 'Blue Crab', whose flower stalk only emerges in June. Such a gap is almost impossible to bridge through home cultivation temperature difference adjustment. But I suppose it can be done in large greenhouses - otherwise, Lao Jiang's 'Kangping' x 'Blue Crab' hybrid seedlings would have to have come from Mars.
In addition, temperature difference can also be used to control pests and diseases in the pot. Especially in spring and autumn, appropriate low nighttime temperatures can inhibit bacterial growth in the pot and pest activity. The ultimate goal is to reduce the use of chemicals and achieve environmentally friendly plant care.
Temperature difference can also increase the thermal expansion and contraction of substrate granules, indirectly achieving the purpose of improving soil quality through the soil's own physical changes.
In short, rational use of temperature difference is the key to cultivating good Haworthia. If sunlight, water, and substrate are the staple food of home-cultivated plants, then the above 3 items can only solve the plant's basic survival needs, while suitable temperature difference is a tonic that can take the plant from basic survival to a comfortable standard of living.

Seven. The effect of fertilizers and pesticides on succulents
If the previous six chapters are all conclusions Lao Jiang reached through repeated testing based on practical experience, then this chapter is a bit of a stretch.
As a stubborn gardening-school adherent (as opposed to the tech-school), Lao Jiang has always upheld the native spirit of China's five-thousand-year agricultural heritage. I have always believed: "Soil is the only reliable source of plant nutrition. Only soil is the indispensable medium for plants to take root and grow. Soil has the ability to protect and regulate itself. When there are pests and diseases, plants will die, ultimately depriving the pests and diseases of their breeding ground. Once the pests and diseases have starved to death, the soil is still healthy soil. When the soil loses fertility, plants will not grow, until nutrients brought by rain and air restore the soil's vitality. Goats that graze on the green grass will ultimately fall on the green meadow and become nutrients for the grassland. Branches full of fresh fruit, although they consume the soil's nutrients, return everything they received to the soil after ripening. In nature, there are no pesticides and no chemical fertilizers, yet natural soil possesses a powerful force that humans cannot replicate..." Although not religious, Lao Jiang has read the agricultural passages in the Bible several times.
This is not Lao Jiang showing off - the truth is I really can't write much. But since this chapter has been decided on, I have to pad the word count somewhat. Below I'll briefly talk about my own understanding of fertilizers and pesticides.
1. The effect of fertilizers on succulents
For plant growth, fertilizer is necessary. "One Hundred Thousand Whys" tells us that the three essential elements for plant growth were discovered by the British. Through burning plants and analyzing the resulting ash, scientists identified large amounts of nitrogen, phosphorus, and potassium, plus trace amounts of other elements. Thus the conclusion was drawn that the three essential elements for plant growth are: nitrogen, phosphorus, and potassium.
Nitrogen is mainly concentrated in the plant's stems and leaves. So supplementing with nitrogen fertilizer can promote the growth of stems and leaves - lush foliage is the credit of nitrogen fertilizer.
Phosphorus is mainly concentrated in the plant's reproductive organs - that is, flowers and fruits. Supplementing with phosphorus fertilizer can promote flower bud differentiation and fruit development. Abundant fruits are the credit of phosphorus fertilizer.
Potassium is mainly concentrated in the plant's root and stem tissues. Supplementing with potassium fertilizer can make plant stems sturdy, roots well-developed, increase lodging resistance, and increase the ability to resist external attacks. Deep roots are the credit of potassium fertilizer.
Apart from the ethereal trace elements, the effects of fertilizers roughly come down to the above 3 points. As for whether home-cultivated succulents need additional nutrient supplementation, Lao Jiang has always held reservations. Referring to the soil mixes in previous chapters, plus regular repotting and soil replacement, slow-growing succulents need almost no additional fertilizer supplementation. Unlike herbaceous flowers, the characteristic of succulents growing only a few leaves a year results in extremely low consumption. Low consumption naturally means eating less, and on top of that, there are several months of dormancy in the year. So for nutrient needs, what's already in the soil is more than enough.
I've never seen succulents suffer from fertilizer deficiency, but I've often encountered root burn from too much fertilizer. The earlier discussion of succulent root osmotic pressure was mainly aimed at over-fertilization. When Lao Jiang first started growing succulents, I was superstitious about the effects of fertilizer. Unexpectedly, every time I fertilized, the plants rotted. As a result, the intended fertilizing effect was never achieved - but I did gain a lot of experience from repotting and soil replacement.
However, nothing is absolute. Being unchanging is relative, while change is absolute. When there is no need for hybridization and pollination, fertilizing is superfluous. But if there is a need for hybridization and pollination, the situation is completely different.
Plant flowering and fruiting consumes large amounts of nutrients, not just the phosphorus we mentioned earlier. Plant flowering and fruiting is an important life cycle, so at this time, all of the plant's tissues cooperate with this important action of reproducing offspring. This includes: stems thickening to prevent lodging from the weight of flowers and fruits. Roots gripping deeper to help absorb more nutrients. Some plants even appropriately shed leaves to avoid blocking insect pollination and fruit exposure to light.
In summary, plants need more nutrients to support flowering and fruiting. Besides the earlier accumulation, more is needed from timely external supplementation. Wild Haworthia are not like cultivated ones. Although wild Haworthia will also grow 3 or 4 flower stalks and produce dozens of flowers, not every flower has a chance to be successfully pollinated - on the contrary, this ratio is more often even zero. (This is determined by the flower structure of Liliaceae plants.) Home-grown ones are different - pollination success rate is much higher, sometimes even a single flower stalk setting ten or twenty seed pods. Mesembs are roughly the same. So home-cultivated succulents, needing to meet the consumption of hybridization and pollination, require more additional nutrient supplementation.
Flowering fertilizer should focus on phosphorus and potassium, with other elements as supplements. It is best applied in liquid form for rapid effect. You can choose professional flower fertilizers like Huayou or Huaduoduo, or directly apply monopotassium phosphate. The application ratio should be controlled at around 1:2000, that is, 1 gram of fertilizer to 2 kg of water. It must be said again here that some experts believe a 1:1000 ratio is more appropriate, but that is under large greenhouse and conservatory cultivation conditions where plants grow vigorously and can handle that concentration. Under home conditions, plants absorb nutrients far slower than in large greenhouses and conservatories, so dilute as much as possible.
Fertilizing should be timed during the flowering period, that is, starting from when the flower stalk emerges, once every half month, applied together with watering. Continue until the seed pods mature. For individuals whose flowering period needs to be controlled or synchronized, apply less or not at all.
That's all Lao Jiang knows about fertilizers. Any more and it would just be nonsense, so I'll stop here. Now let's talk about pesticides.
2. The effect of pesticides on succulents (excluding growth-regulating chemicals)
Succulents rarely suffer from pests and diseases, even though they come from South Africa. The harsh environment of the African continent has given succulents strong adaptability. Probably because they are exotic species, the Haworthia and mesembs I grow at home give me the overall impression of being unappealing to chickens and untouched by ducks - common red spider mites and scale insects are nowhere to be seen. Occasionally a small black fly emerges from the soil, but it's harmless.
However, I've read about pest and disease issues on some growers' blogs, mainly the larvae of fungus gnats and similar flying insects harming seedling roots. Although I've never experienced it myself, I suspect this may be related to the nature of the soil these growers use. These growers add natural components like leaf mold and coal cinders to their media, or even use these materials entirely. Natural things are indeed environmentally friendly, but it's hard to avoid insect eggs and pathogens remaining in them. Over time, it's only natural for bugs to appear.
Lao Jiang doesn't have much experience with pesticide use. Many times, when one or two plants show symptoms of rot or disease, Lao Jiang prefers to use surgical methods to completely eliminate the affected area. In retrospect, I should have focused on prevention. Now that technology is so advanced, not making good use of the power of technology and instead constantly wielding a scalpel to cut here and there is too bloody... So for a period, Lao Jiang also put effort into shallow research on pesticide use. Below I'll briefly share what I've learned.
For ordinary gardening enthusiasts, the most commonly used pesticides are broad-spectrum fungicides like carbendazim, thiophanate-methyl, and chlorothalonil, as well as expired pesticides like carbofuran (carbofuran has been banned by the state due to its high toxicity and high residue). For home cultivation, the above several pesticides are sufficient to handle common pests and diseases. But which specific pesticide to use and how to use it - there are hidden subtleties.
Common diseases of general garden plants include leaf rot, root rot, and a series of harms caused by fungal infection. Each disease, if not treated promptly, will lead to rot of some plant organs or even death of the entire plant. But for South African succulents, bacterial leaf rot and root rot rarely occur (except when wounds from physical damage are not treated promptly). The only thing that poses the greatest threat to succulents is fungal infection, specifically manifested as large-area fungal infection after poor ventilation, humidity, and inadequate sterilization of cultivation media - what we commonly call "fuzz." The probability of outbreak is highest especially at the seedling stage.
It needs to be explained here: "fuzz" on the soil surface is fungal infection, a pathological appearance. But mycelium inside the medium is an inevitable phenomenon of soil organic matter decomposition, a normal phenomenon. Fungal infection uses the plant's tissue cells as a nutrient source, ultimately causing the plant's tissues to rot. While mycelium inside the medium is a saprophytic fungus - a beneficial bacterium that decomposes organic matter in the medium to help plants absorb nutrients, and will not harm the living plant body itself. (Except for the heat generated during bacterial reproduction.) These two need to be treated differently - don't lump them together and condemn them all.
Through the above analysis, we also need to be selective in using antibacterial pesticides. We all know that carbendazim and thiophanate-methyl are broad-spectrum antibacterial pesticides, mainly targeting bacterial infections. While chlorothalonil mainly targets fungal elimination. In the process of home cultivation of succulents, since the main task is resisting fungal infection, preventive application should use chlorothalonil as the main pesticide. To avoid developing resistance, you can alternately use carbendazim and thiophanate-methyl in coordination. For wound treatment after pruning and shaping, carbendazim and thiophanate-methyl should be the main choices, as chlorothalonil's effect is much weaker in comparison. Pesticide use should follow the 16-character formula: "prevention first, alternate use, increase concentration, reduce frequency."
Prevention first means nipping problems in the bud, controlling before signs appear. Don't wait until you see the affected area before applying pesticide - by then, even if controlled, it will affect the plant's appearance and even future health. Generally, the period of seasonal transition is the key point for preventive application.
Alternate use means preventing the development of resistance in fungi. The same pesticide should be used at most 3 times consecutively, then switched to another. Otherwise, once resistance develops, applying pesticide is like watering - completely ineffective. And because you've lost one pesticide that could be rotated, the use frequency of other pesticides increases, causing those other pesticides to also become ineffective due to resistance.
Increase concentration is a pesticide strategy applicable to both animals and plants. For routine diseases and explosive acute infections, increasing the concentration by 30-50% above the label concentration can achieve good results in a short time. This allows the infected individual, in the sterile environment created by high-concentration pesticide, to improve its own resistance through strengthened management and follow-up care, and recover health sooner.
Reduce frequency is relative to increasing concentration. As mentioned above, there are beneficial bacteria in the soil. Sterilizing pesticides, while treating, will also indiscriminately kill beneficial bacteria. And beneficial bacteria are good for improving soil quality and preventing compaction. So pesticide use must take this factor into account. Don't use pesticides too frequently. Give beneficial bacteria appropriate room to grow. In addition, reducing pesticide frequency can also avoid the development of resistance. Recommended preventive application interval is 2 months, and can be appropriately increased during seasonal transitions.

Finally, let me introduce 2 tips:
1. After sowing, if there is continuous rainy weather and the potting soil is too moist, fungal outbreaks are very likely in the pot, and pesticide must be applied at this time. But since the potting soil is already in a very moist state, applying conventional pesticide would undoubtedly add even more water to the already moist environment, which is very unfavorable for seed germination. At this time, you can directly and evenly sprinkle the dry pesticide powder on the pot surface, without needing to dilute with water and spray.
2. Conventional sterilizing pesticides are powder products using talc as a carrier. (The white powder we see is actually talc - the actual pesticide ingredients are invisible.) After dilution and spraying, they form white spots on the plant surface, affecting the plant's appearance and photosynthesis, and are very difficult to remove. It is recommended to let the diluted pesticide sit for 2 hours, and after the talc settles, use only the supernatant for spraying (that is, the active ingredients of the pesticide), which can avoid the above contamination.
The article has now reached 30,000 words, and it's time to talk about the author's own feelings. Lao Jiang feels that summarizing itself is also a process of self-improvement. Through writing, I can recall all the experiences and techniques I've been through before. After all, growing plants is a long-term and leisurely process, and Lao Jiang is also a very casual person - many things experienced along the way couldn't possibly have been recorded at the time, so this writing opportunity is perfect for consolidating them. Of course, the article is a bit long, and finding something valuable among these 30,000 words will probably take some effort... In any case, for those who can read it from beginning to end, Lao Jiang holds boundless respect and gratitude. I hope you keep it up~