Ecological Environment and Man-made Regulation of Cymbidium

Whether the growth and development of Cymbidium is normal or not is closely related to the ecological environment in which it grows. Therefore, in order to plant and raise Cymbidium well, we must first carefully find out its growth characteristics and what kind of ecological environment is needed to meet its requirements. Then, according to the growth characteristics and phenological period of Cymbidium, we should strive to choose superior natural ecological environment or man-made conditions for raising Cymbidium plants. In order to raise Cymbidium well, we must choose natural or man-made control to create an environment suitable for the growth of orchid plants, which is the key to the success of planting and raising Cymbidium.

Cymbidium was originally a terrestrial or semi-terrestrial orchid growing in alpine valleys of Southeast Asia. Due to the long-term development of this ecological environment, it likes warm, high humidity, sufficient light, good ventilation, fresh air and temperature difference between day and night. In order to choose such a good ecological environment, not all of them are found in the high mountains, not to mention the plains. Therefore, while selecting the basic environment, we must also carry out man-made regulation and control in order to achieve the best ecological environment. Our experience in long-term practice is summarized as follows:

I. Lighting

Light mainly refers to sunlight, including artificial light, which is the driving force of photosynthesis of chlorophyll in orchid plants. Without light, chlorophyll can not carry out photosynthesis, and it will not be able to provide necessary nutrition for orchid plants. Different orchids have different needs for light, even the different stages of the growth and development of the same orchid. Cymbidium generally needs light from 15000Lux to 70000Lux, which can be said to be a good light plant. When the amount of light can best meet the needs of the orchid plant, the growth and development of the orchid plant is very sound, tall and straight, the leaf is short and wide, the leaf quality is thick, the leaf color is light green or yellowish green, the pseudocorm is full and full, the flowering rate is very high, the number of flowers is large, the flower color is very bright and shiny. Some people think that the flowering rate is proportional to the amount of light, which is not entirely true, because the more light, the better, it should also have a certain limit. If it exceeds 70000Lux, its photosynthesis slows down, especially in summer and autumn, when the temperature is high, the direct light shines on the leaves of the orchid plant, and the leaves are burned for a long time. This is how what we call "sunburn disease" occurs. Therefore, in summer and autumn, it is necessary to prevent direct light and reduce the amount of light. The methods adopted are as follows: on the one hand, different shading nets are used to control and reduce the amount of light, on the other hand, the ventilation and humidity are increased, otherwise the orchid plant will be hurt.

The light is lower than 10000Lux, that is, insufficient light, less photosynthesis, insufficient nutrition, in this environment, the orchid plant will grow only, the leaf will be thin and long, the leaf color is dark green, the leaf quality is thin and soft, the whole plant is weak and drooping, very lifeless. The flowering rate of this kind of orchid plant is very low, the flowers that can bloom are very few, and the color is not bright and lustrous. Therefore, in the case of lack of light, especially in winter and spring, we should remove the shading net and make the light enter the orchid shed as far as possible. In the long-term rainy season, fluorescent lamps can also be used to make up for the lack of light when necessary.

Second, temperature

From the observation of air temperature in Xiamen for more than ten years, the adaptability of Cymbidium to temperature is relatively strong. No freezing injury was found at the low temperature below 8 ℃ in winter, and some varieties of seedlings in seedling pots were frozen below 0 ℃ in a short period of time. No freezing injury was found in other medium, large seedlings and adult plants. The high temperature sometimes reached 38 ℃ in summer and autumn, and no abnormality was found in plants. However, the early flower buds and spikes will be aborted due to the influence of high temperature, so the adaptability of air temperature to Cymbidium in Xiamen is not to increase temperature but to take effective cooling at a certain stage.

The best temperature of Cymbidium grandiflora is 8 ℃ to 20 ℃ at night and 20 ℃ to 30 ℃ in daytime, especially the flower bud differentiation of three-year-old adult plants begins in June. The temperature difference between day and night must be controlled between 15 ℃ and 10 ℃, so that flower bud differentiation to spike formation can be carried out smoothly, so we must take measures to cool down in this period. First, in late May, the plants ready to bloom were transferred to the natural ecological environment of the cool alpine zone about 1 km above sea level to promote flower bud differentiation and spike formation. In December, the temperature in the plain has dropped, and the temperature difference between day and night is obvious, so it is shipped back to management one after another to provide market sales. Another way is not to go up the mountain, but to move into the orchid shed with protective facilities, import air-conditioning every night, control it at about 20 ℃, restore the daytime temperature during the day, and use artificial control to achieve the required temperature difference between day and night. The former has a low cost but a lot of labor, while the latter has a high cost but saves labor.

Third, humidity

Cymbidium is native to the ecological environment in alpine and canyon areas, and its humidity requirements are relatively high. Comrades who first raise orchids often have an one-sided understanding of humidity as the number of times the plant is watered in the basin, which is wrong. The humidity we refer to includes the water holding capacity of the plant in the basin and the relative humidity in the air outside the basin.

The plant material in the basin is required to maintain a certain amount of water, but not stagnant water, to maintain good ventilation, too much water accumulation in the basin is bound to affect poor ventilation, so that the root soaked in water, lack of oxygen suffocation to death. If the water in the basin is too dry, the roots have no water to absorb and the orchid leaves continue to evaporate, which is bound to cause dehydration and death of the whole plant. Therefore, watering in the basin must first be based on the nature, size and thickness of pots and plants, different seasons, high and low air temperature, and all stages of plant growth and development (the orchids placed in the same orchid shed should be unified). Seriously consider when to water, how much, how to water, this is a more complex and difficult problem in orchid cultivation.

The humidity outside the basin refers to the relative humidity of the air in the orchid shed. Cymbidium requires that the best relative humidity in the air is 80% to 90%. In order to achieve such humidity in the farm, it must be solved by artificial control. For example, the particularly dry air in autumn and winter is disadvantageous to the growth and development of Cymbidium, so we need to increase the humidity in the air in this season. We can use humidifiers to automatically control the spray. Can also use soil method: in the orchid shed construction, first consider under the orchid shelf, dig into a stagnant pool of the same size as the orchid shelf, the pool is covered with coarse sand or gravel, and the water can be diverted into the pool in the dry season, so that the orchid plant can be placed on the pool. Because of the large evaporation surface, the air humidity in the orchid shed can be maintained to meet the needs of the orchid. If the humidity can not reach the standard, spray water can be increased on the orchid shelf and on the channel. This kind of soil method has low cost and can also achieve ideal relative humidity. There are many Rain Water in spring and summer, and the temperature is high, and the relative humidity in the air in the orchid shed sometimes exceeds 95%, even reaching a state of saturation, which hinders the transpiration of the orchid plant, and the water absorbed by the root cannot be consumed, which is bound to destroy the metabolism of the orchid plant. In this case, the humidity must be artificially reduced in time, and the method is to stop spraying and discharge the water from the pool under the orchid shelf. Open the doors, windows or fences around the orchid shed, use electric fans or exhaust fans, exhaust fans and other machinery to increase the air flow in the orchid shed and discharge the humidity, so that the humidity in the orchid shed will fall, so that the orchid plants in the orchid shed can retain the best humidity in different stages, so that the orchid plants can grow healthily.

IV. Ventilation

In an ideal place for orchid cultivation, we should not only pay attention to the selection and control of light, temperature and humidity, but also pay attention to ventilation and fresh air. Because the ventilation is good, the air is fresh, and the diseases, insect pests and physiological obstacles are reduced. The wind is required in the whole process of growth and development of Cymbidium, that is, it can be seen that the leaf tail of the plant can float, so that the water vapor and polluted gas from the leaves can be blown away by the wind immediately. this can promote the smooth circulation of root water absorption and leaf transpiration, and make the plant grow rapidly. Especially from June to August every year, when the light is strong, the temperature is high and the humidity is high, it often makes the orchid shed produce a muggy environment and water vapor stagnates, which is a big taboo of orchids, which not only destroys the metabolism of orchid plants. at the same time, it promotes the occurrence and rapid spread of diseases and insect pests, and the dust in the air will also affect the respiration and photosynthesis of the orchid plant, hindering its growth and development, so the air should keep convection. Get some fresh air. At the same time, we should also pay attention to the air convection should be limited, but also according to the season to regulate, such as convection is too large is bound to hurt the orchid leaves. In winter, the outside temperature is low, and the air-conditioning enters the orchid shed, which is disadvantageous to the growth of orchid plants, so it is necessary to consider reducing or stopping, or changing air at noon.

The four environmental factors mentioned above are not isolated, they promote and restrict each other, so when we adopt man-made regulation and control of various factors to make up for the deficiency of the natural ecological environment, attention must be paid to putting the above four factors into the scope of regulation and application at the same time according to different seasons and different growth stages in order to maintain the best ecological environment. (Wu Lianxing)