South African succulent plant home cultivation - temperature chapter
Article abstract: Content about succulent plants, home cultivation of South African succulent plants - temperature chapter, a comprehensive introduction follows.
VI. The influence of temperature difference on succulent plants and its control
1. The influence of temperature difference on succulent plants
For most species of succulent plants native to South Africa, the most suitable temperature for growth is between 12-28 degrees Celsius, which should also be the average high and low temperatures during the growing season in the native region.
In regions represented by Hangzhou, where Laojiang is located, due to the convergence and struggle of north and south air currents, it is often the case that cold air is followed by subtropical high pressure. There are only about 4 months of the year, from May to June and October to November, when the temperature can maintain between 12-28 degrees Celsius. For most other months, it is either too cold or too hot, resulting in a sudden transition from heavy clothing to short sleeves, and then suddenly back to sweaters after wearing short sleeves for only two days. (This is also the reason why spring and autumn clothing don't sell well in Hangzhou)
This kind of climate is barely bearable for humans, but for plants, especially succulent plants, it is quite problematic. Some people say that large temperature differences can promote plant growth. It's true that diurnal temperature differences can promote plant growth. However, you may not have understood the principle of this growth. Let me explain it to you slowly...
The quality of plant growth depends on the accumulation of nutrients in the body. During the day, photosynthesis in plants is a process of manufacturing nutrients. Within a reasonable upper temperature limit, the higher the temperature, the stronger the photosynthesis, and the more nutrients produced. We can consider this process as adding points to the plant's nutrient accumulation.
At night, due to the absence of light, most plants stop manufacturing nutrients, and the score is zero. However, the transpiration of plants continues. Transpiration is the process by which plants rely on environmental temperature to evaporate water from the leaves, and at the same time, rely on the capillary effect brought about by evaporation to absorb water from the roots. This process consumes nutrients in the plant's body, and for plant nutrient accumulation, it can also be seen as a deduction process. The higher the environmental temperature, the greater the transpiration, and the more deductions. Therefore, the amount of 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. The higher the temperature during the day, the more nutrients the plant manufactures, and the lower the temperature at night, the fewer nutrients the plant consumes. The effect of diurnal temperature differences is reflected here. (Why are X-J grapes sticky sweet? Why can X-J tomatoes taste like persimmons? It's not because of the diligence of the farmers, but because of the climate with "wearing a fur coat in the morning and wearing silk in the afternoon".)
Now that we know this principle, I believe no one will argue with me about the difference between sudden temperature changes and diurnal temperature differences.
In fact, sudden temperature rises and drops due to climatic reasons are not only beneficial to plants but can also cause extremely serious damage, not only disrupting the normal physiological order of plants but also prompting various unexpected accidents. For example, in spring, after the temperature has risen for a while, plants begin to show signs of growth, and you have already started watering and fertilizing busily. Suddenly, the temperature drops, and the new leaves that have just grown will immediately become rigid. Not to mention the consequences of the water and fertilizer you have applied. Just this rigid leaf may trigger your urge to cut your head off. You say you won't cut it, okay, don't cut it. In a few months, the rigid leaf will start to grow, with a pointed top and a round bottom, forming a gourd shape... This is still good. If all the leaves are like this, it can still be considered a new variety to deceive yourself. But what if there is only one gourd leaf among a circle of good leaves? Do you still cut it or not? As for accidents, it's fine if the temperature drops suddenly after a high temperature, as South African succulents can handle short-term freezing. But it's麻烦 if the temperature rises suddenly after a low temperature. In the middle of winter, if the temperature suddenly rises to 25 degrees, and the greenhouse is stuffy, the temperature can suddenly soar to 50 degrees. When you come back at night, you will find a whole greenhouse of steamed meat waiting for you to uncover...
In addition to these, there are also pests and diseases, fungi, etc., all related to sudden temperature changes.
The summary of this section needs to be stated separately - temperature differences can promote the growth and accumulation of nutrients in succulent plants, but only if they are controlled diurnal temperature differences. Sudden temperature changes caused by weather are harmful to plants.
2. How to create and utilize temperature differences
Family cultivation environments define that it is difficult for us to achieve the perfect artificial temperature differences of greenhouses. (Greenhouses rely on the sealing effect of polyester film to store heat under the sun, thereby increasing the daytime temperature to create larger temperature differences.) However, family environments have their advantages. As long as you're not living in a pergola, it's at least warm in winter and cool in summer, and it's still possible to avoid extreme temperatures. So how to create temperature differences requires some ingenuity within the not-so-obvious temperature differences at home.
(1) How to create temperature differences in winter
Although I mentioned earlier that I still advocate following nature and not doing too much, for the severe winters in the south, following nature is equivalent to admitting that succulent plants, especially Vaseyi plants, have nearly half a year of dormancy. This is unfair to the many southern flower friends. (Why do people in the north have heating... We don't have coal in the south, but we have natural gas... Who doesn't have a few heating fees?) So, the temperature difference in winter is mainly achieved through daytime insulation.
Insulation first requires consideration of sealing. Some flower friends in Shanghai have used large storage boxes or built "pigeon coops" outside the windowsills to achieve considerable success. I support these two methods. I didn't advocate them when discussing water control, but when it comes to insulation in winter, I think these two methods are feasible.
However, both methods have their flaws; storage boxes are too small in volume, which is insufficient for those with a larger cultivation scale. Pigeon coops can be effective during the day, but at night, when the cold wind blows from outside the window sill, the internal temperature immediately drops to the outdoor temperature. Taking the coldest temperature of minus 5 degrees in Hangzhou in winter, within a week, the leaves of Vaseyi plants will turn white and foggy, and then start to rot in the spring. Unless you install air heating lines and temperature controls, which people with an electrician's license are afraid to use, why? You'll know if you get an electrician's license.
In the end, it's better to do less, and wrapping the existing flower shelves is a more environmentally friendly method. Common flower shelves are usually divided into two types, wooden and metal. For wooden shelves, it is recommended to use sunlight boards for direct wrapping (which is more aesthetically pleasing and has good insulation effects) except for the front and bottom surfaces. The other four sides can be fixed with wood screws. The front can be made into a curtain form with greenhouse film or soft glass to facilitate opening. Place several water trays under the shelves to increase humidity and store the heat from the day to release it slowly at night to prevent the temperature from dropping too fast when the sun can't shine on it.
This kind of treated shelf needs to be placed in a place where it can get sunlight during the day. Generally, on a clear day with an outdoor temperature of about 5 degrees Celsius, the temperature inside the greenhouse can rise to about 25 degrees Celsius. And at night, no matter how low the outdoor temperature is, the temperature inside the greenhouse can be slightly higher than the indoor temperature. (Does anyone have a room temperature below 0 degrees? If so, please raise your hand, Laojiang will organize donations and sweaters for you)
This method is suitable for Vaseyi and Aizoaceae plants.
(2) How to create temperature differences in summer
This topic is quite tragic. The sauna-like weather in the south is pervasive, and there seems to be no good way except for air conditioning. During the day, it's not much talked about, with eggs being fried on manhole covers happening every day. It's slightly better at night, with the outdoor temperature slightly below 30 degrees, but indoors, the zero-degree temperature difference between day and night is hard to change. You say you have air conditioning, but after all, only a few families have central air conditioning. With split-system air conditioners, only the bedrooms will have air conditioning at night. You're not going to put your plants in the bedroom, are you? Some students have installed small air conditioners in greenhouses or greenhouses, which is of course a good method. But if everyone does this, what would Laojiang have to nag about? After all, there are more students who prefer practical methods...
We've talked about it before, Vaseyi plants are in deep dormancy in the summer, marking the end of the growing season. Compared with winter dormancy, summer dormancy is a physiological cycle behavior, and controlled dormancy allows plants to accumulate the energy for the next growing season, which is relatively beneficial for plants. So, in the summer, our goal in creating temperature differences is not growth, but maintenance. Appropriate enlargement of the temperature difference during the summer dormancy period can prevent plants from experiencing physiological disorders due to high temperatures. It can also help dissipate the heat accumulated in the potting soil during the day through the relatively low temperature at night, thereby maintaining the health of the roots.
So, in the summer, the temperature difference is mainly reduced at night, while the day is left to nature, as long as shading is done well. At night, without using air conditioning equipment, methods such as spraying and electric fans are used for physical cooling. Spraying needs to be done until the soil surface changes color and the plant surface is covered with water droplets, then turn on the fan to blow. The evaporation of water can take away heat. Laojiang has tested this method and the data is as follows - in the severe summer season, after 8 pm, when the temperature around the flower pot is 32 degrees, the temperature can be reduced to 29 degrees after one hour of spraying and blowing. Then, by opening the windows for ventilation or using the air conditioning breeze from the room, the lowest temperature in the greenhouse at night can reach the outdoor temperature (about 27 degrees Celsius), which is enough for Vaseyi plants to go through the summer dormancy.
This method is only suitable for Vaseyi plants. For Aizoaceae plants, Laojiang suggests not watering and leaving them to grow naturally in the summer. As long as they are healthy seedlings over 2 years old, the more they are exposed to the sun, the more spirited they become.
(3) How to create temperature differences in other seasons
In winter, we focus on daytime insulation, and in summer, we focus on nighttime cooling. Then, in the golden spring and autumn seasons, we need to get close to nature.
Getting close to nature means making the temperature difference in the cultivation environment close to the natural temperature difference outdoors. In the south, there is a natural large temperature difference of about 10-15 degrees Celsius between day and night in spring and autumn, along with fresh outdoor air and natural dew, which is a waste not to take advantage of.
There's no need to go into detail about the methods here, such as natural ventilation, forced ventilation with fans, and露天 cultivation, etc. As long as the greenhouse becomes a pergola, the goal is achieved. Of course, be careful of the sudden cold spells in spring and the return of the subtropical high pressure.
(4) The use of temperature differences
Having learned to create temperature differences, we can use them to regulate plant growth. The plump or short plants you see on Japanese websites are also the result of extensive use of temperature differences.
For succulent plants, the theoretical dormant period is the reproductive growth stage, which is manifested by weak growth on the surface, but the accumulation of nutrients in the plant body reaches a peak. And the time is different for different families - Vaseyi plants in early summer and Aizoaceae plants in deep autumn.
During this period, by increasing the temperature difference, we can enhance the accumulation of nutrients in the plant, which will make the plant plump due to the increase in dry matter, and the thickening of stems and leaves can correct the etiolation accumulated during the growing period. Combined with the slow growth caused by the low temperature at night, the plant will naturally show the characteristics of being short and fat. Even, enough temperature difference can offset the etiolation caused by insufficient light, but Laojiang hasn't tested this, so I'm just mentioning it in passing.
Furthermore, temperature differences provide external conditions for the flowering of plants. Plants that have been adjusted by temperature differences will have more uniform and vigorous flowering in the subsequent flowering period. Whether it's for Vaseyi hybridization or Aizoaceae ornamental flowers, it is very beneficial. Imagine, a group of living stone flowers blooming en masse overnight, that feeling, unless you see it with your own eyes, you can't feel it.
Temperature differences can also control the activity of pests and diseases in the pot. Especially in spring and autumn, the appropriate low temperature at night can inhibit the growth of bacteria and the activity of pests, ultimately reducing the use of chemicals and achieving the purpose of environmentally friendly gardening.
Temperature differences can also increase the thermal expansion and contraction of planting material particles, indirectly improving the soil quality through the physical changes of the soil itself.
In short, the reasonable use of temperature differences is the key to cultivating good Vaseyi plants. If we say that sunlight, water, and planting materials are the staple food for family cultivation plants, then the above three can only solve the problem of food and clothing for plants, while the appropriate temperature difference is a kind of tonic that can make plants enter a well-off level on the basis of food and clothing.
That's all the content of the South African succulent plant home cultivation - temperature chapter, and no unauthorized reproduction is allowed!