Culture method of potted poinsettia

Poinsettia, also known as ivory red, old Laijiao, Christmas flower, etc., is an evergreen shrub plant of Euphorbiaceae, native to Central America and widely cultivated in tropics and subtropics. It is cultivated in most provinces, autonomous regions and cities in China. It is common in parks, botanical gardens and greenhouses for viewing. Stem and leaf medicine has the effect of reducing swelling, so let's take a look at the breeding method of potted poinsettia.

The growth habit of poinsettia

Poinsettia originated in the Tasco region of Central America and Mexico and was introduced to the United States by Joel Poinsett, the first U.S. ambassador to Mexico, in 1825. Short-day plants, like warmth, the suitable temperature for growth is 18: 25 ℃, 18: 24 ℃ from April to September, 13: 16 ℃ from September to April of the following year, and the winter temperature is not lower than 10 ℃. Like to be moist, poinsettia is more sensitive to water, as long as the water supply is sufficient during the growing period. Like the sun, in the stem and leaf growth period need sufficient sunshine to promote the stem and leaf growth rapidly.

The breeding method of poinsettia

1. Cutting: there are mainly two ways of cutting propagation of poinsettia: semi-hardwood cutting and tender wood cutting, as well as old root cutting. No matter which method of cutting propagation is adopted, the cuttings of poinsettia should be cut in the early morning. Because the water content of cuttings is more abundant at this time. When cutting cuttings, the incision should be smooth, and the split epidermis and xylem should be cut off so as not to rot and affect the healing and rooting.

2. Striping: poinsettia generally adopts the method of high-pressure reproduction, and the time of crimping should be carried out from April to July. Choose woody branches, generally choose healthy and full branches of the first year, and peel rings in smooth parts. The width of ring peeling is about the same as that of branches in ring stripping, and it is generally appropriate to take 3-4 cm. The root system can grow in about two months after pressing, and at this time it can be cut off and planted in the basin to form a new plant.

The culture method of poinsettia

1. Soil: poinsettia likes loose and well-drained soil, which is generally mixed with 3 parts of vegetable garden soil, 3 parts of humus soil, 3 parts of rotten leaf soil, 1 part of rotten cake fertilizer, and a small amount of slag.

2. Temperature: poinsettia likes to be warm and afraid of cold. When entering the room in the middle and last ten days of September every year, the ventilation should be strengthened to make the plants adapt to the indoor environment gradually, and the room temperature should be kept at 15 ℃ to 20 ℃ in winter. At this time, it is the period of bract discoloration and flower bud differentiation. If the room temperature is less than 15 ℃, the flowers and leaves will be stunted. It will enter the flowering stage after mid-December, and it should be ventilated gradually.

3. Illumination: poinsettia is a short-day plant with sufficient light and strong phototropism. Sufficient light should be given all the year round, and the discoloration of bracts and the period of flower bud differentiation and flowering are more important. If the light is not enough, the branches are easy to grow, susceptible to diseases, the flowers and colors are dim, and if they are placed in a dark place for a long time, they will not blossom and will lose leaves in winter. In order to advance or delay flowering, you can control the light, generally give 8 to 9 hours of light every day, 40 days can bloom.

4. Fertilization: poinsettia likes fertile sandy soil. In addition to adding organic fertilizer and horseshoe slices as base fertilizer when potting and changing pots, sesame paste residue liquid fertilizer diluted 5 times and fully mature should be applied every 10 to 15 days during the growing and flowering season. After entering autumn, 0.3% compound fertilizer can be applied once a week for 3 to 4 times in a row to promote bract discoloration and flower bud differentiation.

5. Watering: poinsettia is not resistant to drought and moisture. Watering should be flexibly mastered according to the weather, basin soil and plant growth. Generally, watering should keep the basin soil moist without stagnant water, but watering should be reduced after flowering. Watering should be paid attention to evenly, to prevent too dry and too wet, otherwise it will cause the lower leaves of the plant to yellowing and falling off, commonly known as "off-foot", or uneven branch growth.

6. Heart picking: after 3 weeks of planting, the root system of poinsettia has grown. At this time, the heart can be removed. The temperature is raised to 28030 ℃ during the day and 23 ℃ at night. The temperature is often increased by spray, lasting for about two weeks. See the bud grow out, then slowly lower the temperature, 25: 28 ℃ during the day, the humidity should also be reduced, during this period, according to the uniformity and fullness of the plant, the second coring can be carried out to replenish nutrients. Combined with dwarfing agent treatment.

7. Pruning: poinsettia changes the pots of dormant old plants before and after Ching Ming Festival, cuts off old roots and weak branches, and promotes its germination of new techniques. it needs to be heart-picked twice in the process of growth, the first in late June and the second in mid-August. Large amount of fertilizer and water should be controlled in cultivation, especially before the plant is set in autumn. When the branch is 20 to 30 cm long, it begins to be shaped and bent, in order to make the plant short, the flower head neat, evenly distributed, and improve the ornamental.

8. Plant control: in the process of cultivation, poinsettia needs to use plant growth regulators to dwarf the plant height in order to meet the requirements of commercial flowers. In addition, it is also very important to maintain the consistency of temperature between day and night during cultivation, and it should be monitored at any time. When the temperature difference between day and night is more than 3 ℃, it can be sprayed 1 to 4 times after full coring to restrain the stem length.

Disease and pest control of poinsettia

1. Grey mold

[symptoms] Botrytis cinerea mainly occurs in winter, when poinsettia blossoms. Once it is rainy and wet, it can harm inflorescences, bracts, leaves and branches of poinsettia. Generally speaking, water-immersed disease spots begin to appear from the tidbits. After that, the disease spot was covered with a robe of pathogens, and the pathogens continued to spread to the bracts. The bracts produced water-immersed discolored spots at the initial stage, and then gradually expanded into irregular shapes, and the pathogens extended to the branches, producing yellowish brown to brown spots on the branches. in the later stage, the disease spots were obviously sunken dark brown, and in severe cases, the disease spots were dry.

[prevention and control] make use of the closed facilities to create an ecological environment with high temperature and low humidity to control the occurrence and development of Botrytis cinerea. Most of the indoor humidity of the facility is higher than 90% at night. after pulling in the morning, the vents should be opened immediately to ventilate and drain moisture, reduce the indoor humidity, and control the development of the disease with a lower temperature. When the indoor temperature rises and accelerates after 9 o'clock, close the vents and quickly raise the indoor temperature to about 32 ℃.

2. Root rot

[symptoms] generally occur more seriously in the high temperature season, and are also easy to occur when the cultivated soil water content is high. The phenomenon of wilting appeared in the early stage of the plant, but if the base of the stem was examined, the phenomenon of light brown constriction could be seen, but there was no corruption or hydrolysis in the infected plant, and then the disease spot gradually spread upward, and the wilting phenomenon became more and more serious, and the disease spot was slightly sunken in yellow brown. In the later stage, the tissue of the disease spot disintegrated, causing the plant to wither to death due to serious lack of water, and sometimes the whole plant was yellowed in water, resulting in decay and death. The white hyphae can be seen near the ground and can be extended to the cultivated soil in severe cases. When the root is sick, it often causes root rot, which affects the normal growth of the plant at the initial stage and leads to death in serious cases.

[prevention and control] rotation was carried out in ①: rotation in mildly diseased fields every other year, and in seriously diseased fields at intervals of 3 to 5 years. ② deep ploughing and soil improvement: increase the application of organic fertilizer, rational drainage and irrigation, and enhance disease resistance. ③ strict seed selection: eliminate unqualified seeds. Mix seeds with 50% carbendazim wettable powder at 0.5% of seed weight. During the onset of ④, the stem base of peanut was sprayed with 1000 times of carbendazim wettable powder, 25kg / mu each time.

3. Leaf spot

[symptoms] Leaf spot disease mainly occurred in spring and summer, and most of the disease spots began to occur in the old leaves. In the early stage, purplish red to brown spots were produced on the leaves, and the disease spots were nearly round to irregular, and then the disease spots gradually expanded, and most of the disease spots could heal each other to form a large disease spot, and in the later stage, the center of the disease spot gradually changed to grayish brown. In severe cases, the lesion tissue is gangrenous, causing the leaves to twist and dry up.

[prevention and treatment] ① removed the diseased tissue in time and burned it centrally. ② rotation (soil can be changed in greenhouse). ③ is not suitable for spraying plants. ④ began to spray from the early stage of the disease to prevent the spread of the disease.

4. Whitefly

[symptoms] the adults and larvae of whitefly prefer a dense and shady environment and cluster on the upper leaf back of poinsettia to suck juice with prickle mouthparts, so that the leaves fade or appear chlorotic spots, affecting photosynthesis, resulting in poor plant growth. Honeydew excreted by worms often causes mildew and dirt. Adults have a yellowing tendency.

[control] the first instar mobile larva is the most vulnerable, followed by the newly emerged adult, which is sensitive to pesticides and is suitable for spraying control. Whitefly generally occurs in large numbers at high temperature and low humidity, and the peak period is from late September to late November. The most suitable period for prevention and treatment is late September, and the spraying time is 6 ~ 10:00 in the morning.