The method of regulating the florescence of poinsettia culture

Poinsettia blossoms from November to December under natural light conditions, and it is necessary to deal with it if it wants to blossom earlier or later.

Short-day treatment is mainly carried out in advance of flowering, that is, when the plant is basically or fully formed, the plant is covered with a small arch shed with black film, and pay attention to close shading. If there is light leakage that does not achieve the desired effect (usually about 100 lux of light intensity can prevent flower bud differentiation and development), the dark time is 14: 15 hours a day, that is, it is covered at 6: 7 p.m. every day, and the shading should be carried out continuously from 8: 00 a.m. to 9 a.m. the next day. Do not ask for a break every day, if interrupted, the pre-treatment will not work.

When the temperature is too high, between 22:00 at night and 2 o'clock the next day, it is best to take off the black film and ventilate the leaves to avoid withering and yellowing caused by high temperature, and is conducive to the formation of flower buds. After 22-28 days of treatment, the flower bud differentiation was completed, and the flower bud at the top of the branch was obviously inflated; the bracts began to turn red at about 35 days, stopped shading treatment when one of the branch bracts turned red completely, and entered the flowering stage at 60-70 days. As a result, the initial treatment time of the plant can be calculated according to the flowering time. If the National Day light intensity is needed, it is better to treat it in the middle of July.

Delayed flowering is mainly treated with light at night, which can prevent flower bud differentiation as long as there is a light intensity of 100 lux around the plant height, and the effect is good from 10:00 in the evening to 2 o'clock in the morning.

Culture methods and points for attention of poinsettia growth habits 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.

Propagation method of poinsettia

1. Cutting propagation:

The cutting propagation of poinsettia mainly includes semi-hardwood cuttage and tender wood cuttage, as well as old root cuttage. 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 propagation:

Poinsettia generally adopts the method of high-pressure reproduction, and the time of striping should be 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. Culture method of poinsettia

1. Soil:

Poinsettia like loose, well-drained soil, generally use 3 parts of vegetable garden soil, 3 parts of humus soil, 3 parts of rotten leaf soil, 1 part of rotten cake fertilizer, plus a small amount of slag.

2. Temperature:

Poinsettias like warmth and fear 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. Lighting:

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 rich 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. Pick the heart:

After 3 weeks of planting, the root system of poinsettia has grown. At this time, the coring can be removed. The temperature is raised to 28 ℃ during the day and 23 ℃ at night. The humidity is often increased by spraying for about two weeks, and then the temperature decreases slowly. During the day, the humidity is 25: 28 ℃, and the humidity is also reduced. During this period, according to the uniformity and fullness of the plant, the second coring can be carried out to supplement nutrients. Combined with dwarfing agent treatment.

7. Pruning:

Poinsettia changed the old dormant plants before and after Ching Ming Festival, cut off the old roots and weak branches, and promoted its germination. 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. Control strain:

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. Matters needing attention in breeding poinsettia

The main results are as follows: (1) poinsettia is sensitive to water, as long as there is enough water in the growing period, the stems and leaves grow rapidly. On the contrary, lack of water or sometimes dry and sometimes wet, will cause leaves to fall off. Therefore, the control of water content in poinsettia directly affects its growth and development.

(2) poinsettia is a light-loving flower, which grows healthily under strong light. Except for shade and cooling in midsummer, it is advisable to have sufficient light in other seasons. Even in summer, shading can lead to slender stems and larger leaves.

(3) poinsettia enters the shed in mid-late October. When entering the shed, the two ends of the shed should be opened to reduce the temperature difference between inside and outside the shed, avoid yellowing or falling leaves, and affect the quality of flowers. In winter, the temperature should be kept above 20 ℃ during the day, and the temperature at night should not be lower than 15 ℃, otherwise the growth is slow, which is not conducive to the formation of bracts, and the temperature is too low, which will cause yellow leaves and fallen leaves. Poinsettia indoors should be turned into pots every day to maintain uniform light and prevent branches from bending and growing. After the shed, it is necessary to strictly control the watering amount of poinsettia, the humidity is too large, flowers and leaves are easy to mildew; lack of water in the basin, leaves are easy to yellowing and falling off. Water less after flowering. 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.

The nicknames for the cultivation and management of poinsettia are: Ivory red, old Laijiao, Christmas flower, Christmas red, poinsettia. Also known as Christmas flower (known as Christmas red in Taiwan), it is a famous red flower used to decorate at Christmas because its bright red is full of Christmas atmosphere. The red parts that are thought to be flowers are actually leaves, while the real flowers are in the middle of the leaf bundle. Poinsettia is usually 60 cm to 3 m high and its dark green leaves are about 7 to 16 cm long. The top leaves are fiery red, red or white, so they are often mistaken for flowers. There are also literary works and related legends called this.

Poinsettia culture method: 1. Cultivate soil with loose and well-drained soil, generally use 3 parts of vegetable garden soil, 3 parts of humus soil, 3 parts of rotten leaf soil, 1 part of rotten cake fertilizer, plus a small amount of slag. two。 Coring in 3 weeks after planting, the root system has grown, then can be coring, coring when leaving 4-6 leaf nodes, the temperature increased to 28-30 ℃ day temperature, night temperature 23 ℃, often spray to increase humidity, lasting about two weeks, see the bud grow out, and then slowly lower the temperature, 25-28 ℃ during the day, humidity should also be reduced, during this period according to the plant uniformity, fullness, the second coring, supplement nutrients, combined with dwarfing agent treatment. 3. The temperature of poinsettia prefers 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. 4. Poinsettia likes sufficient light and strong phototropism, so it belongs to short-day plants. 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. 5. Fertilizing poinsettia prefers 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. 6. 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. 7. Before and after pruning, the old dormant plants were changed, the old roots and weak branches were cut off, and the new techniques were promoted. The heart should be removed 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. In the process of plant cultivation, plant growth regulators are needed to dwarf the plant height in order to meet the requirements of high consistency 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.

Poinsettia management: poinsettia likes a warm, moist and ventilated environment, is not resistant to low temperature, excessive sunlight and lack of light are also not conducive to growth, during the growth period to do a good job of fertilizer and water management, heart-picking and other maintenance work. When watering, we should pay attention to avoid being too dry and too wet, otherwise it will cause the leaves of the lower part of the plant to yellow and fall off, the branches grow unevenly, and when the summer weather is hot, we should appropriately increase the amount of water, but do not accumulate water in the basin, so as not to cause root rot. Other seasons depend on the dry and wet condition of the basin soil. Poinsettia is not strict on the soil, the general rich sandy soil will do. When changing the basin, the mature organic fertilizer should be added in time as the base fertilizer, and liquid fertilizer should be applied every half a month or so in the growing and flowering season. After autumn, some fertilizers rich in potassium and phosphorus can be added to promote flower bud differentiation and ensure the purity of bract leaves. Poinsettia grows faster after it enters the growth period, so you must pay attention to picking the heart and fixing the head, otherwise the branches will grow too high, which will affect the shape of the appearance and reduce the ornamental value. Poinsettia can be propagated by cutting, cutting a section of branches in spring and summer and smearing some plant ash on the cut to prevent the incision from rotting, which can take root after being inserted into the soil for about 25 days. In addition, poinsettia juice is poisonous, do not touch it when picking the heart and cutting, in order to avoid causing skin discomfort.