How to raise poinsettia
Soil selection
Poinsettia likes loose and well-drained soil. We usually use 3 parts garden soil, 3 parts humus soil, 3 parts humus soil, 1 part decomposed cake fertilizer, and add a small amount of slag to mix. The prepared soil is not only beneficial to the growth of poinsettia, but also enhances the disease resistance of poinsettia.
Poinsettia requires cleanliness, good drainage, relatively low soluble salt content, sufficient ion exchange capacity, storage and supply of essential plant elements, standardized production of substrates, no soil pests, germs, nematodes and weed seeds, stable biochemical and chemical effects of substrates, and no release of amines by heating and chemical treatment. The cultivation substrate is often mainly peat, mixed with one or more substances such as perlite, vermiculite, ceramsite, sawdust, bark and river sand. The substrate should be sterilized by steam heating at 7l℃ for 30 minutes, and the pH value should be 5.5 ~ 6.5.
Temperature control
Poinsettia likes warm environment. Poinsettia bonsai can be seen in any season except winter. Every September, when the weather starts to get cold, the poinsettia should be completely put indoors. At this time, it is necessary to ensure that the indoor temperature is about 15 degrees to 20 degrees. Above or below this temperature, the growth of poinsettia will be threatened.
The optimum growth temperature of Poinsettia is 18 ~ 25%, 18 ~ 24℃ from April to September, and 13 ~ 16℃ from September to April of the following year. The optimum night temperature is 16 ~ 2 1℃, the optimum daily temperature is 2 1 ~ 27%, the temperature is lower than 16℃, the growth is slow, and 13℃ is stagnant, so it cannot bear the temperature below zero. In the case of strong wind, freezing damage will occur at 5℃, exceeding. The initial temperature of leaf stretching is 5 ~ 7℃, and the growth rate is the fastest at 25℃, and the growth rate slows down when it is higher than 25℃. Internode length and plant height increase with the increase of temperature difference between day and night. The optimum temperature for flower bud differentiation is 65438 06 ~ 2L℃. When the temperature exceeds 2L℃, the development speed slows down, and the temperature in the later stage of growth is maintained at 15 ~ 17℃, which is beneficial to the development and discoloration of bracts. Night temperature of 25℃ can delay flower bud differentiation.
Fertilization method
Poinsettia is a kind of fertilizer-loving flower, which is highly dependent on water. During the poinsettia growing season, sesame sauce residue liquid fertilizer must be applied every 10 ~ 15 days, diluted 5 times and fully decomposed. When the weather is good, you can water it properly, usually to keep the basin soil moist without water.
Poinsettia likes fertilizer, and it needs 20: 20: 20: 20 fertilizer in the early 2-3 weeks of growth. In the main growth period of 7- 10 days, apply 1 N: P: K = 20: 10: 10 fertilizer or "Huiyou" 17-5- 19 poinsettia. After August to before flowering, apply 1 N-P combined liquid fertilizer every 7 ~ 10 days. When it is close to flowering, apply more phosphate fertilizer to make the bracts bigger and more colorful, but each fertilization should not be too thick, let alone fattening. The morning after application, pour 1 times water. In the low light period in winter, generally from the beginning of June 1 1 to before the sale, the frequency and concentration of fertilization are halved.
Poinsettia likes fertilizer, and there are two kinds of formula fertilizers, one is coated slow-release granular fertilizer and the other is liquid fertilizer. Based on nitrogen, the fertilization concentration of poinsettia is 65438+ 1 time per week, the nitrogen concentration is 250 ~ 300mg/L, and the ratio of nitrogen, phosphorus and potassium is 20: 10: 20. Poinsettia needs different fertilizers at different stages of growth. The first month is a critical period, and the concentration of nitrogen and potassium can be appropriately increased. When the flower bud differentiates to the stage where the bracts turn red, the ratio of nitrogen, phosphorus and potassium should be adjusted to normal, and the contents of phosphorus and potassium should be increased at flowering stage, and the nitrogen content should be appropriately reduced.
Dressing and shaping
If you want a good pot of poinsettia, you must trim and shape it. When the branches grow to 20 to 30 centimeters, you can start shaping and composing. The purpose of this is to make the plants short, the flower heads evenly distributed and improve the ornamental value.
Watering method
Poinsettia is very sensitive to the reaction of fertilizer and water during its growth. Uneven watering, wet and dry will cause adverse reactions. Too much watering, soft leaves droop or cause rotten roots; Insufficient watering caused the leaves to curl and wither. The water should be dry and wet, the temperature is not high at the initial stage of growth, the plants are not big, and the water should be less; In summer, the temperature is high, the branches and leaves grow vigorously, and the water demand is large. Water 1 time every morning and evening, and at the same time, according to the weather and the dry and wet conditions of the basin soil, it is necessary to spray water on the ground for humidification. Generally, water in spring and autumn 1 ~ 2 days 1 time.
Water quality is an important factor for the success of poinsettia cultivation. The main factors affecting water quality are EC value * * * conductivity * * *, pH value, carbonate, sodium ion, calcium ion, boron, fluorine, sulfur and iron. Iron and manganese exist in water in reduced soluble state and oxidized insoluble state. If the content of iron and manganese is too high, the water should be precipitated before use. Excessive calcium and magnesium will not harm plants, but foliar spraying will cause salt deposition, and acid treatment can remove carbonate and bicarbonate from water. Fluorine comes from superphosphate and perlite, and the boron content is 0.3 ~1mg/L.
Lighting requirements
Poinsettia is a typical short-day flower. It takes less than 12 hours of light every day to differentiate flower buds. The natural differentiation period of flower buds is from the beginning of 10 to the beginning of March of the following year. Flower bud development needs longer dark time than flower bud differentiation, and the suitable time is 15 hours. During flower bud development, the involucral bracts stop developing and turn green before they are fully developed. Flower bud differentiation is very sensitive to red light, and short-term or extremely weak red light will also affect flower bud differentiation, so light should be prevented during flower bud differentiation. Moonlight contains less red light and does not affect flower bud differentiation. Use100w * * * incandescent lamp, light it for 2 hours every day, and it will continue to grow nutritionally without flower bud differentiation during the short sunshine season in winter.
What should I do if the poinsettia falls?
1, poinsettia is afraid of drought and waterlogging.
If it is too dry, it will make the plants lack of water, and the leaves will curl and fall off a lot. If the pot soil is too wet, the plant canopy density is high, and photosynthesis cannot be carried out well, leading to malnutrition and defoliation.
Therefore, water every 2 days in spring; In summer, the foliage is lush, the growth is fast, and the amount of watering is large. In case of heavy rain, drainage should be carried out, or potted plants should be moved indoors before it rains. Water once a day in autumn morning 10, and move the potted bridge into the greenhouse at the end of autumn, the plant grows slowly, and the frequency and dosage of watering and fertilization gradually decrease; To prevent freezing and keep warm in winter, water every other sunny day at noon, and the water temperature should be close to the soil temperature.
2. Avoid direct glare in summer.
Potted plants should be placed in a well-ventilated place, and the distance between pots should be 50 cm. Water should be sprayed frequently on the ground to increase the air humidity, which can effectively control the defoliation of plants caused by high temperature drying.
Poinsettia is a happy sun.
Poinsettia is a short-day plant, which needs sufficient sunshine during the growth period of stems and leaves to promote the rapid growth of stems and leaves. In order to make the bracts turn red in advance, the sunlight care should be controlled within 12 hours to promote flower bud differentiation. If it is illuminated for 9 hours every day, the bracts will turn red after 5 weeks. The soil should be loose and fertile sand with good drainage. Potted soil is a mixture of cultivated soil, humus soil and sand.
4. Poinsettia likes to be fat.
More nitrogen fertilizer is needed in the growing period, and insufficient nitrogen fertilizer will make the lower leaves of plants fall off. In addition to applying late-acting base fertilizer when serving, the pancakes with alcohol are applied fertilizer every 7 days or so within one month after removing the core, which is easy to cause root rot. Don't apply more fertilizer during flowering, or the leaves will be in a hurry. Before entering the house in winter, apply 40% fermented human feces.
Poinsettia likes warm, humid and cool climate.
Not cold-tolerant, the suitable humidity for growth is 15 ~ 20℃, and it should be kept above 15℃ and not lower than 5℃ at night in winter, otherwise the leaves will fall off easily. If it opens the window to blow cold air in winter, it will also cause a lot of leaves to fall. Therefore, low temperature is the main reason for defoliation. Therefore, poinsettia is best preserved in a stable environment with high temperature in winter.
Toxicity analysis of poinsettia
1, Poinsettia is toxic: Some experts think that the whole plant of Poinsettia is toxic. But watching and placing will not cause harm to human body and environment.
2. Poisoning symptoms: the white milk in its stem contains a variety of toxic alkaloids, which will cause * * * board. If you touch the panel, it will easily lead to allergic symptoms such as redness, fever, itching, local papules, etc. If you eat stems and leaves by mistake, it may lead to gastrointestinal reaction and nervous disorder, and in severe cases, it may easily lead to poisoning and death.
3, poisoning treatment: consider vomiting or gastric lavage and diarrhea as appropriate; Take egg white, activated carbon and sugar wat; You can also drip 5% glucose saline intravenously to give stimulants to keep warm; If blood pressure drops, give norepinephrine; If breathing is difficult, oxygen can be given and artificial respiration can be carried out if necessary.
4, warm reminder: Poinsettia is best not to put in the bedroom, you can put it on the balcony, living room. And be sure to put this flower where it is not easy for children to get it. Do not touch poinsettia when coring and cutting, so as not to cause discomfort to the panel.