South African succulents home cultivation - Sunshine chapter
About the knowledge introduction of this succulent plant, the home cultivation of South African succulents - Sunshine chapter, let's take a look together.
III. Sunshine and the pursuit of sunshine by South African succulents
1. The role of sunshine
Everything grows with sunshine, and it feels stuffy without basking in the sun for a day. In ancient times, prisoners were often tortured by being locked in a dungeon, deprived of the right to bask in the sun, which shows the importance of sunshine for living things.
Compared to animals, plants are more dependent on sunshine because light can help plants perform photosynthesis and produce nutrients. Someone might say, plants have roots, and it's the roots that absorb nutrients... I can only say, please take out your junior high school biology textbook. The roots of plants absorb only raw materials, which are transported to the leaves and then undergo photosynthesis through the catalysis of chlorophyll, carbon dioxide, and light to eventually produce sugars that the plant can consume. It's like the blood flowing in your veins is not rice.
Sunlight refers to full-spectrum natural light, which is the light that can reflect 7 single-color visible lights after passing through a prism, and natural light includes not only visible light but also UVA, UVB, UVC, and other invisible wavelengths. The visible spectrum's red and blue light, as well as UVA, UVB, UVC, play a major regulatory role in plant growth. There are now high-tech red and blue plant growth lights on the market that are said to work well, but the cost of using them is probably much higher than the price of ordinary home cultivation plants. Just knowing about this is enough, don't take it seriously.
Old ginger thinks that visible light is easy to understand, but the role of invisible light is often overlooked. Fortunately, I have a deep understanding of the components of invisible light when I used to raise turtles and birds, so I'm taking this opportunity to share it all. Otherwise, I might get prostatitis from keeping all this knowledge to myself. Fortunately, this article is not going to be published on a forum, it's just for internal communication, so old ginger can write whatever he wants, and you can choose to read it or not.
2. Introduction to invisible light in sunlight
UVA, with a wavelength of 320-400nm, also known as long-wave black spot effect ultraviolet light, has strong penetrating power, can pass through most transparent materials, damage the epidermal cells of living things, promote cell aging, and cause tanning in humans. This is what MM's prevent day and night. For succulent plants, this band of light can promote epidermal cell aging, making the shell hard and thick, not as watery-looking, but at the same time, the plant's resistance will increase, and its resistance to physical damage from the outside world will greatly increase, especially in a good neighborhood environment where plants placed outside can greatly improve their resistance and survival rate under the trampling of birds and squirrels. More importantly, moderately aged epidermal plants can avoid sunburn from sudden increases in sunlight, so giving appropriate moderate UVA exercise is essential for home cultivation.
UVB, with a wavelength of 275-320nm, also known as medium-wave erythema effect ultraviolet light, has moderate penetrating power. Only about 2% of it reaches the ground after passing through the atmosphere. This band of ultraviolet light can help animals with mineral metabolism and vitamin D formation. We晒太阳 actually means we are basking in UVB, so I like to call it life-ray. For plants, UVB is part of promoting photosynthesis, but its promotional effect is opposite. From the appearance, it can cause plants to become dwarfed, thereby accumulating a large amount of nutrients in the roots and stems of the plant, ultimately aiming to improve the plant's physique through nutritional accumulation and promote flowering and fruiting. Without UVB, all plants in the world would become soft and weak like leek seedlings. From the perspective of home cultivation of succulent plants, UVB irradiation can make plants dwarfed and compact, which is more aesthetically pleasing and increases resistance. The long-nosed king mentioned earlier is a negative example.
UVC, with a wavelength of 200-275nm, also known as short-wave germicidal ultraviolet light, mainly functions to sterilize. Excessive irradiation can cause a large number of cell deaths, leading to skin cancer in humans and scorching and withering in plants. I like to call it灭杀-ray. Fortunately, its penetrating power is the weakest, unable to pass through most transparent glass and plastic, and most of it is absorbed by the ozone layer during its passage through the atmosphere. (Therefore, protecting the ozone layer is very important...) For home cultivation of succulent plants, since drugs are generally used in small amounts, it is necessary to accept appropriate UVC irradiation for the health and sterilization needs of the plants. It can kill harmful bacteria on the plant surface or in the surrounding environment and also promote the metabolism of epidermal cells, similar to the effect of UVA.
Okay, the introduction to invisible light is over, and years of hard work have finally turned into black and white words on paper. I feel great!
3. The pursuit of light by plants
So, what are the characteristics of the pursuit of sunshine by South African succulent plants in a home environment? If you are smart enough, you should already have an idea after reading the "physiological characteristics" and "sunshine" sections above. If you still don't have an idea, it doesn't mean you are slow, it just means you are eager to learn. Since you are so eager to learn, let's continue to listen to me talk.
In a home environment, as mentioned earlier, due to shading, there is no direct sunlight most of the time, and due to the interception of objects such as awnings and windows, even the light that comes in lacks sufficient invisible light (such as UVB, which is lost by more than 80% under the filtration of a single-layer glass, mainly due to the lead element in ordinary glass), and excessive artificial lighting can cause an overdose of UBA and UVC. Originally watery plants may either get sunburned or become old and rough. It can be said that the environment for home cultivation of succulent plants is a pathological environment, a congenitally deficient environment. This has nothing to do with how much fertilizer you use or how much water you pour, this is congenital. Unless you are willing to knock a hole in your ceiling, but I don't think your neighbor upstairs would agree.
This congenitally deficient environment can lead to many adverse consequences, such as: plant stretching, reduced resistance, fungal outbreaks, bacterial spread, or sunburn, sun death, drying like a mummy... We often hear people say when growing flowers, "Grow flowers outdoors, they don't grow well indoors, they are good for people, not for flowers," etc. These sayings may come from ordinary people, but if you study them carefully, they actually have scientific principles. The key issue is this "light" word.
In fact, there are solutions, besides smashing the ceiling, there are many other ways to correct or make up for the unfavorable conditions of insufficient light. For example, drugs, water control, lighting methods, increasing temperature differences, and treating differently according to seasons, etc. "Drugs" are not my specialty and must be abandoned. "Water control" I classify under the "water" section and won't discuss it now. This chapter will first talk about the other two methods.
(1) Tips for effective use of sunshine by balcony gardeners
Most balcony gardeners should have a balcony (I admit this is a redundant sentence, if you don't have a balcony, what's the point of growing flowers). Most balconies are enclosed, and although enclosed balconies have good lighting conditions, as mentioned earlier, glass can block ultraviolet light, so I suggest opening the windows for as long as possible under your control. This is a very good method, especially for Aizoaceae plants, which are much better in a full-spectrum scattered light environment than in missing-spectrum direct light. I once did an experiment at home, comparing the living stone flowers cultivated under scattered light on the balcony without obstruction with those of the same age, size, and variety but exposed to sunlight through a glass window in the bedroom. The former was clearly shorter, fatter, and had comfortable epidermal aging, not as watery as the latter. Even in summer, the dormancy was not obvious. After potting, I had an even deeper experience. The former had a clear main root, thick, not too woody, with well-developed lateral and capillary roots, and brought up a large soil clod, while the latter was much weaker, although also very healthy, but looked like a greenhouse-raised child, unable to withstand the wind and rain.
If you are growing Haworthia, you also need to note: if the balcony has windows on three sides, place the Haworthia plant on the east side, and on the west side of the window, place enough tall greenery or hang a shading net. If the balcony only has a south-facing window, it needs to be placed on the west side, the reason being that Haworthia needs moderate short-daylight. The early morning sunlight that can shine into the balcony just meets this requirement. As for shading, if your balcony has an awning, you don't need to consider it at all. Because the angle of sunlight changes with each season, the more summer it is, the more direct the sunlight, and at noon, when shading is needed, there is often no sunlight shining into the balcony. If you like your plants to be watery in the summer, a single-layer 50% shading net is enough. If the plant still looks dry after shading, then恭喜 you, because you can play with the potting soil again.
(2) Choice of lighting in different seasons
Based on the characteristic that South African succulent plants are all winter-growers, home cultivation should fully utilize the growing season. Because the climate in the south is distinct in all four seasons, the low temperature in winter and the high temperature in summer are not something that Haworthia or Aizoaceae can bear, so during these two seasons, most plants at home are in a state of dormancy, the difference being that Haworthia is in a shallow dormancy in winter and a deep dormancy in summer, while Aizoaceae is the opposite. There are a few students with good conditions who will use heating or homemade cooling water curtains to artificially adjust the temperature to keep the plants growing. However, I believe most students can only do as I do, listen to it and let it naturally go into dormancy. (A few students who still give a lot of water and fertilizer in summer or winter, for fear that the plants won't eat enough, are not included in the discussion) This way, the growing period of the plants is only in spring and summer. From the climate in Hangzhou, the general growing peak is from October to December and from April to June.
How to use these months most efficiently also determines the growth rate of your plants. Some people often envy others' plants for growing fast, but in fact, the conditions of others' homes are not much different from yours. The difference is that they have utilized these months well, while your plants spend all their energy on root development during these months.
To make good use of this time, giving the plants sufficient natural light is essential. Taking Haworthia as an example, in spring, after a continuous period of cloudy and rainy weather and low temperatures in winter, the plants are in a state of shallow dormancy, accumulating a lot of toxins in their bodies, and the bacteria and eggs in the potting soil begin to stir. At this time, it is necessary to gradually increase the light, and the windows that have been closed for months should also be opened. On one hand, the natural warming of the potting soil in the sun can stimulate the plants to secrete growth hormones, and on the other hand, the ultraviolet light in the sun can kill harmful bacteria and eggs in the potting soil. However, be careful not to expose the plants to sudden sunlight, as mentioned earlier, UVA and UVB are fatal to plants before their epidermal cells have time to age. The same is true in autumn, except that in addition to paying attention to the intensity of sunlight and the plant's adaptability, it is even more important to pay attention to the plant's condition in the clear and cool autumn weather, because in the south, the intensity of ultraviolet light in autumn is much higher than in summer. Generally, the amount of sunlight in autumn is adjusted so that the leaves of the plant are no longer kept green. If the leaves turn red, it means that the light is too strong. For plants just waking up from summer dormancy, more shading is needed.
The so-called stretching mentioned earlier does not include the temporary stretching or heightening caused by rapid growth of plants in spring and autumn. The best time to control stretching is not during the peak of growth but before the dormancy period, that is, at the end of December and the end of June in the south, because during this time, the day and night temperature differences are large, and the plants are just entering the period of nutrient accumulation. During this period, appropriately increasing the amount of light helps the plants to become dwarfed and compact, and at the same time, it increases the speed of nutrient accumulation, which not only controls (or corrects) stretching but also helps with physiological preparation before dormancy.
The above is a sunlight scheme that maintains the fastest growth speed while keeping the plant shape to a maximum degree. Plants grown this way may look slightly watery, not very strict in terms of compactness, shortness, and fatness. This may not be suitable for those who pursue extreme plant shapes and do not consider growth speed or compare the longevity of plants, but it is enough for ordinary home hobbyists who enjoy keeping plants alive, healthy, and taking photos to share on forums for beginners to comment on.
The introduction to the home cultivation of South African succulents - Sunshine chapter is introduced here for everyone to learn and understand!