How to grow poinsettias? Cultivation methods, precautions and key points of water and fertilizer management
This year, a new family has been added to the Magenta family: the new variety "Sunshine", launched by Guangzhou Yihua Gardening Co., Ltd., is about to be released. The characteristics of "Sunshine" are very outstanding: the crown is uniform and the branching is very good. Compared with Yihua's main variety "Gold Award", "Sunshine" grows faster, 7 days to 10 days earlier than "Gold Award", and only takes 90 days from seedling to finished product. It has strong cold resistance and can grow normally even when the temperature is as low as 12°C. Recently, a reporter interviewed Zhou Shiliang, general manager of Guangzhou Yihua Gardening Co., Ltd., who explained in detail the key points in the production process of "Sunshine".
Lighting control
At the seedling stage above the pot, the roots of the seedlings are relatively fragile, and the light intensity should be reduced. Zhou - the top of the greenhouse should be covered - 75% shade net. If the seedlings are planted in summer, you should spray some water on the ground to increase the air humidity. When the roots of the seedlings are not yet well established, too much light will cause the seedlings to lose water and dehydrate. After the seedlings enter the shed - one week later, it is better to increase the light and keep it at 20,000 lux.
After about 5 days, observe whether the plant roots have grown to the bottom of the pot. If they reach the bottom of the pot, you can choose to pinch. After topping, the light should be controlled between 15,000 lux, and shading should be continued for two days. Plants that have received care are injured. At this time, remember not to expose them to the sun. After two days of shading, moderately increase the light and keep it between 15,000 and 20,000 lux. After 45 days of growth on the seedlings, the plants bloom at about 25 cm; if it is summer, blackout treatment is needed. In winter, turn off the lights, that is, stop nighttime lighting, to ensure that the plants' lighting time does not exceed 12 hours. After the bracts turn color, the light is controlled at 15,000 lux and finished after 50 days.
Temperature and humidity management
The optimal growing temperature for "Sunshine" is between 18°C and 28°C, and the lower temperature cannot be below 12°C. Otherwise, plant growth will slow down and the finished product will be delayed. At the seedling stage, the nighttime temperature should not be below 15°C, otherwise plant growth will slow down; during the day it should be controlled below 32°C, and greenhouse ventilation should be ensured, with humidity not lower than 50%. After topping, the temperature in the greenhouse should be kept within 30°C, and humidity should not be lower than 65%, because if the light is too strong, the temperature is too high and it is too dry, it will affect the germination and growth of the plant's side buds.
During the flowering period, the nighttime temperature must be below 24°C. - The magenta flowering stage is also called the induction cycle, which refers to the time required for finished flowers to change color. During the induction cycle, if the temperature is higher than 24°C, it will affect the plant's flowering and growth. At this stage, be sure to pay attention to reducing humidity; do not exceed 70%, otherwise diseases such as gray mold are likely to occur. During the induction cycle, the temperature is preferably controlled between 16°C and 18°C, making the plant color more vivid. After the bracts change color, the temperature can be controlled between 15°C and 30°C.
Water and fertilizer management
At the small seedling stage, water is only poured into the pot; when watering, only water. During the growth of - magenta, as long as it is watered, it must be - thoroughly, and should not be only half-watered. The plant roots grow to the bottom of the pot for - fertilization. Nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer are mixed in a ratio of 20×9×20 or 20×10×20, diluted with water to 200 times and dissolved in water. Then observe the plant's growth, water when there is water shortage, and fertilize each time you water. After the plant enters the vigorous growth period, the fertilization concentration can be increased to 600 times or 700 times. After the bracts are red and transparent, appropriately reduce the fertilization concentration, diluting 800 times to 1000 times. Throughout the entire growth process of "Sunshine", the pH value should be kept between 5.8 and 6.2.
Pest and disease control Pest and disease control is mainly based on prevention: spray alcohol-based insecticide once a week, and spray once every two weeks. The most prominent pest of "Sunshine" is whitefly, whose growth period is very long. Whitefly takes only 7 days to 10 days from egg to adult. Its reproduction speed is faster, so the focus is on prevention. Seriously, only the plants can be destroyed. During the spring seedling stage, growers also need to pay attention to mosquito larvae, because when the seedling roots are not strong enough, mosquito larvae will damage the seedling roots. In this regard, a layer of lime can be spread on the greenhouse floor to reduce the humidity in the greenhouse, inhibit pest reproduction, and spray conventional drugs.
The most serious disease of "Sunshine" is gray mold. The focus is on prevention: control greenhouse humidity, do not let it get too high, and maintain good ventilation. When the disease occurs, treat it with conventional drugs. It is also necessary to pay attention to the production process to ensure growing space between plants, and do not let the leaves touch each other. If it is too crowded, it will cause plant growth problems.