What to do when poinsettia leaves turn yellow and drop? Raise the temperature, fertilize frequently, water less

Because the poinsettia's flowers are very beautiful, and its fiery red flower color looks very festive, many flower lovers choose to grow one after seeing it. However, during the growing process, due to improper care or long-term neglect, the poinsettia will get sick, and what follows is yellowing leaves. So what should you do when poinsettia leaves turn yellow and drop? It is actually very simple, just find the cause and solve it. The specific methods will be introduced in detail by the editor below.

I. What to do when poinsettia leaves turn yellow and drop, find the cause

In the poinsettia cultivation methods, it is mentioned that poinsettia has requirements for soil, light, water, etc., so yellowing and dropping leaves may be caused by one of these aspects not meeting the standard. What to do when peace lily leaves turn yellow, the editor will analyze them one by one for everyone from several aspects such as water, light, temperature, and fertilization.

II. Causes and solutions for poinsettia leaves turning yellow and dropping

1. Not repotting in time

When cultivating poinsettia, a relatively small pot is generally chosen for initial planting, but after a period of cultivation, the plant will slowly grow and become much larger, with dense branches and leaves. At this time, the small pot can affect the poinsettia's continued growth, and the potting soil loses nutrients, thus causing the leaves to turn yellow.

Solution: When cultivating poinsettia, it is necessary to repot in time according to its growth condition, and the soil needs to be loosened frequently so that nutrients and water can better nourish the roots and avoid soil compaction.

2. Potting soil too dry/too little watering

When poinsettia leaves turn yellow and drop, besides not repotting in time, the first thing to consider is whether watering has been done properly. When cultivating poinsettia, if there is too little watering, or if the weather is dry and the light is strong, it is easy to cause the leaves to turn yellow.

Solution: In the hot summer or autumn, the poinsettia needs to be placed in a spot with sufficient sunlight, but it is best to water it thoroughly, and it is also necessary to replenish water in time and spray water to increase air humidity.

3. Too much watering

What was said above is that too little watering causes poinsettia leaves to turn yellow and drop. In fact, if there is too much watering, the same symptoms will also appear. If there is too much watering, it will cause water accumulation in the pot. At this time, the poinsettia's roots will lack oxygen, and root rot may occur. These will cause the leaves to turn yellow and drop.

Solution: When cultivating poinsettia, it is necessary to water reasonably. While ensuring sufficient water, avoid water accumulation. If root rot is found, the rotten roots should be cut off in time to avoid continued infection.

4. Too much light

Poinsettia can be said to be a short-day plant. Under suitable light intensity, the leaf color will become more red and vivid, but the summer sun is too strong. If ventilation is not provided in time and air humidity is not increased, it will cause the plant to wilt, the leaves to turn yellow, and the leaves to drop.

Solution: In summer, the poinsettia should be placed in a well-ventilated place, with a spacing of 50 cm between pots, and water should often be sprayed on the ground to increase air humidity. This can effectively control the leaf drop caused by high temperature and dryness. In other seasons, normal light is fine, but avoid direct cold wind.

5. Temperature too low

When poinsettia leaves turn yellow and drop, besides the above reasons, temperature cannot be ignored either. It is understood that poinsettia is not cold-tolerant, and the most suitable temperature for growth is 15-20°C. Once it is below 5°C, if it is not moved indoors in time, it will cause leaf drop. In addition, if a window is opened once in winter and cold wind blows on it, the poinsettia will drop its leaves.

Solution: If it is low temperature that causes poinsettia leaves to turn yellow and drop, flower lovers should appropriately raise the temperature in winter, keep the temperature constant, and place the plant in a relatively stable environment for care.

6. Improper fertilization

Poinsettia likes fertilizer, and its growth needs various trace elements, especially nitrogen. If nitrogen fertilizer is insufficient, the poinsettia leaves will be dull and yellow, and are easy to fall off.

Solution: When repotting each year, apply sufficient base fertilizer at the bottom of the pot. After pruning, apply dilute cake fertilizer water once every 7 days, and topdress before flowering. Do not fertilize during the flowering period, otherwise it will cause scorching of the leaf bracts. Before bringing it indoors in winter, apply a small amount of compound fertilizer, which helps it overwinter. When fertilizing, be careful not to apply too much to avoid burning the roots.

As beginners, many people find that when they first buy a poinsettia, its leaves are still very green, but after growing it for a period of time, the leaves begin to turn yellow. This is actually because you have not done things properly. As long as everyone follows the above requirements, yellowing leaves and such are not a problem. Regarding poinsettia leaves turning yellow and dropping, the editor has introduced this much here, hoping to bring help to everyone.

What to do when poinsettia drops leaves, what is going on?

Poinsettia is a very popular plant, with leaves covered in bright red, looking very festive. But if cultivated improperly, poinsettia will show leaf drop and yellow leaves. Let us understand the causes of poinsettia leaf drop below. Once we find the causes, we can solve the poinsettia leaf drop problem.

Poinsettia likes light. Under suitable light intensity, the leaf color will become more red and vivid, but the summer sun is too strong. If ventilation is not provided in time and air humidity is not increased, it will cause the plant to wilt, the leaves to turn yellow, and the leaves to drop.

Therefore, in summer, the poinsettia should be placed in a well-ventilated place, with a spacing of 50 cm between pots, and water should often be sprayed on the ground to increase air humidity. This can effectively control the leaf drop caused by high temperature and dryness. In other seasons, normal light is fine, but avoid direct cold wind.

Poinsettia is not cold-tolerant. The most suitable temperature for growth is 15-20°C. After entering winter, the temperature should be kept above 15°C and cannot be lower than 5°C. If it is not moved indoors in time and the temperature is not controlled properly, it will cause leaf drop. In addition, if a window is opened once in winter and cold wind blows on it, the poinsettia will drop its leaves.

Since low temperature is the cause of poinsettia leaf drop, the temperature should be appropriately raised in winter, kept constant, and the plant should be placed in a relatively stable environment for care.

Poinsettia likes moisture but fears waterlogging. The potting soil cannot be too wet. If watered too much, the plant cannot carry out photosynthesis well, and poor growth will cause leaf drop. If watered too little, it will cause physiological water shortage in the plant, and the leaves will curl and fall off in large numbers.

Therefore, poinsettia should be watered appropriately, not too much. Usually in spring, water once every 2 days. In summer, when branches and leaves are lush, the plant grows faster and has a larger water storage demand, so it can be watered once a day to ensure sufficient water, and water should often be sprinkled to increase humidity. For outdoor cultivation, in case of heavy rain, shelter it from the rain in time.

Poinsettia likes fertilizer, and its growth needs various trace elements, especially nitrogen. If nitrogen fertilizer is insufficient, the leaf color will be dull and it will easily fall off.

When repotting each year, apply sufficient base fertilizer at the bottom of the pot. After pruning, apply dilute cake fertilizer water once every 7 days, and topdress before flowering. Do not fertilize during the flowering period, otherwise it will cause scorching of the leaf bracts. Before bringing it indoors in winter, apply a small amount of compound fertilizer, which helps it overwinter. When fertilizing, be careful not to apply too much to avoid burning the roots.

In real life, growing plants is a very long process, and it takes a great deal of time and energy, which tests everyone's patience. The more attentively you treat the plants, the better they will grow, and the flowers they produce will also be more vivid.

What to do when poinsettia leaves are not red, causes and solutions for leaves not turning red

Because of its bright flower color, long flowering period, and moderate price, poinsettia is deeply loved by consumers. But many flower lovers have told the editor that the leaves of poinsettia are always not grown red. What is the reason? Let us take a look below with the editor of wed114 wedding website at what to do when poinsettia leaves are not red, understand the causes and solutions for leaves not turning red, and also an introduction to poinsettia cultivation methods.

Introduction to poinsettia

Poinsettia is a plant of the genus Euphorbia in the family Euphorbiaceae, also known as Christmas flower. It is a red flower used for decoration at Christmas. It originated as a certain color-changing foliage plant from the Taxco region of Mexico.

Poinsettia is usually 60 cm to 3 m tall, and its dark green leaves are about 7 to 16 cm long. Its topmost leaves are fiery red, red, or white, so they are often mistaken for flowers, while the real flowers are in the middle part among the leaf clusters. The flowering period can last from December to February of the following year. During the flowering period, it coincides with Christmas and New Year's Day, making it very suitable for the festive atmosphere of the holidays.

Poinsettia can be used as a medicinal plant and has the effects of invigorating blood and resolving phlegm, and setting bones and reducing swelling.

What to do when poinsettia leaves are not red

Cause 1: Long-term lack of light

Solution: With insufficient light, poinsettia is not only not conducive to growth, but also prone to disease. So not seeing red bracts is still a small problem. It is already very fortunate that symptoms such as yellow leaves and root rot have not appeared. Hurry and move your poinsettia to a place with sufficient sunlight. Its red bracts, I believe, will appear very soon.

Cause 2: Not yet in the flowering period

Solution: The poinsettia flowering period can last from December to February of the following year. If its flowering period has not yet arrived, that is, it is still in the growth period, the green leaves may be constantly sprouting, so the red bracts that flower lovers see are naturally relatively few.

Cause 3: Insufficient fertilization

Solution: Insufficient fertilization is fatal to the growth of poinsettia. A poinsettia lacking fertilizer is often short and weak. Was Mama.com Encyclopedia right? Hurry and apply some special plant nutrient fertilizer to it. This is a very good nutrient for it to sprout and grow red bracts.

How to cultivate poinsettia

Many people do not know much about how to cultivate poinsettia. Not long after buying a poinsettia home, the leaves wither. Below, the editor will introduce the cultivation methods for poinsettia.

1. Poinsettia fears both drought and waterlogging. Therefore, each watering must be thorough, and after the pot surface looks dry, water timely again, and frequently spray water on the leaf surface. In winter, water should be appropriately controlled during cultivation.

2. Poinsettia has relatively high requirements for temperature, humidity, light, etc. If the temperature is too low or too high, light is insufficient, ventilation is poor, or water and fertilizer are improper, the leaves will turn yellow and fall off, and it will also fail to bloom. Poinsettia is a short-day plant. During the day, the light duration must be ensured, while at night it must be kept absolutely away from light (including lamplight), which is conducive to flower bud formation.

3. Poinsettia likes fertilizer. From August to October, mainly use phosphorus fertilizer, applying fertilizer once every 10 days. Alum fertilizer water can also be used to promote the growth of bracts.

4. For potted poinsettia, the plant height should preferably be controlled at 40-50 cm. Appropriate methods such as withholding water, withholding fertilizer, bending branches, and topping can be used to control its height.

5. For potted poinsettia, a mixture of 2 parts garden soil, 2 parts leaf mold, and 1 part compost can be used as the substrate.

Potted care of poinsettia

To care for poinsettia well, it is necessary to do a good job in fertilizer and water management during the growth period, control topping, and keep it warm and protected from cold.

Watering should be even to prevent excessive dryness or wetness, otherwise it will cause the lower leaves of the plant to turn yellow and fall off, commonly known as "bare legs," or uneven branch growth. During the plum rain season and summer showers, prevent water accumulation in the pot. After rain, tilt the pot to pour out water in time, or move it indoors together with the pot before rain. In summer, the weather is hot and water demand is high. Water thoroughly with clean water every morning, and observe in the evening. If the potting soil is found to be dry, water once more, and the amount can be smaller this time. In spring and autumn, generally water once every 1-2 days, depending on the weather and whether the potting soil is dry or wet.

Cultivation and fertilization work cannot be ignored. Two to three weeks after potting, a small bamboo slice can be used to loosen the potting soil so that the soil air circulates, and then some liquid fertilizer can be applied, using 20% decomposed human urine or soybean water. From mid-August to October, the number of fertilizations needs to be increased, about once every 10 days, and fertilizer for several kinds of flowers should be appropriately added, and the concentration can also be slightly stronger, using 30% decomposed chicken, duck, or pigeon manure water. This can promote full growth when flower buds are forming.

After poinsettia is potted, it grows relatively fast, so topping must be controlled. Otherwise, the branches will grow too tall, easily fall over in strong wind, and affect the beauty of the shape. Topping can be divided into two types according to need: straight-head or trellised display. The straight-head form means that after the last topping in June, the branches are allowed to keep growing and can reach a large plant height of 60-70 cm. The trellised display requires that when the topped growth reaches 10-15 cm, lead wire is cut into 15-20 cm sections, with the upper end bent into a hook shape and the lower end inserted into the potting soil. The upper end hooks each branch from top to bottom to the pot surface. After about 10 days, when the branches continue to grow about 15 cm, guide the branches horizontally along the edge of the pot, and after another 10 days, guide the branches that have reached the pot edge upward. From mid-September to late October, use thin bamboo poles 30-40 cm long to tie each flower head. If the branches are uneven in height at flowering time, they can be adjusted, tying the tall ones downward and pulling the short ones upward. This method takes more work, but it can make the potted flowers neat. Many dwarf poinsettia varieties introduced from abroad can achieve the goals of short plants, large flowers, and neat flower heads simply through topping control.

Poinsettia should be moved indoors for care before the middle ten days of October each year, that is, before Frost's Descent. If too late, it will suffer cold damage; if too early, the indoor temperature is high, which will cause the plant to grow leggy. When first moved indoors, place it in a ventilated place; by mid-October, place it in a warm place facing south and exposed to sunlight, no longer exposed to cold wind, so as to avoid yellow leaves and leaf drop. Generally, in early to mid-December, the top leaves of the poinsettia turn red and, set off by the green leaves, appear especially red and vivid.

Pest and disease control of poinsettia

I. Diseases

Mainly include stem rot and gray mold caused by fungi, and leaf spot caused by bacteria, etc. In addition to regular spraying of fungicides, auxiliary work such as ventilation and humidity reduction should also be done well in the greenhouse to reduce pathogens. Tools should be disinfected in time to prevent cross-infection, and diseased plants should be cleaned up in time to reduce sources of infection. In winter, sulfur fumigators or sulfur-containing smoke bombs can be used to kill fungal spores in the air.

During greenhouse cultivation, poinsettia is easily infected by diseases and pests such as gray mold, root rot, stem rot, and leaf spot, and there have been many targeted studies at home and abroad.

1. Gray mold

It mainly occurs in winter, which is exactly the flowering season of poinsettia. Once there is continuous rain, humidity, and no sunlight, it often becomes uncontrollable and can harm poinsettia inflorescences, bracts, leaves, and branches. Generally, water-soaked lesions first appear on the inflorescences. Afterward, the lesions are covered with a layer of pathogenic fungal conidia, and the pathogen continues to spread to the bracts. In the early stage on the bracts, water-soaked faded spots appear, which later gradually expand into irregular shapes. The pathogen then spreads to the branches, producing yellow-brown to brown lesions on the branches. In the later stage, the lesions clearly sink downward and become dark brown. In severe cases, the lesion areas become dry and withered, completely losing ornamental value. The pathogen is Botrytis. The pathogen is almost everywhere in the entire greenhouse. It can survive on dead plant tissues or other organic matter and has a wide host range. It can survive at temperatures from 0 to 38°C. As long as there is moisture, it exists. If the greenhouse is too humid, cold and cloudy, and lacks light, after 1-2 days the pathogen produces a large number of spores that float in the air and begin to infect plant tissues.

2. Root rot and stem rot

They can infect adult plants and can also infect during the seedling bed stage, causing serious losses. They generally occur more severely in high-temperature seasons and are also very likely to occur when the cultivated soil has high water content. In the early stage, the plant shows wilting. If the stem base is examined at this time, a light brown constriction can be seen, but the infected plant shows no rot or hydrolysis. Afterward, the lesions gradually spread upward, and the wilting also gradually becomes more serious. The stem lesions are slightly sunken and yellow-brown. In the later stage, the tissue at the lesion disintegrates, causing the plant to wither and die due to severe water shortage. Sometimes the whole plant becomes water-soaked and yellowed, and eventually dies from rot. Near the ground, white mycelium can be seen, and in severe cases it can spread to the cultivation soil. When the roots are affected, root rot often occurs. In the early stage, it affects the normal growth of the plant, and in severe cases it leads to death. The main pathogens are Phytophthora, Rhizoctonia, Pythium, etc. When rooted cuttings are potted, they are most susceptible to Rhizoctonia, especially when the stem is injured or fertilizer salts accumulate on the surface of the medium.

3. Pythium

It appears in adult poinsettia plants. It may already have invaded at the cutting stage, and when the environment is suitable for reproduction, it worsens, causing root rot and death. High temperature and excessive irrigation (stress conditions) can cause Phytophthora damage.

4. Leaf spot

It mainly occurs more severely in spring and summer, and the lesions mostly start on old leaves. In the early stage, purple-red to brown small spots appear on the leaves. The lesions are nearly round to irregular. Afterward, the lesions gradually expand, and most lesions can merge with each other to form a large lesion. In the later stage, the center of the lesion gradually turns gray-brown. In severe cases, the lesion tissue becomes gangrenous, causing the leaves to twist and dry up. The pathogen is Cercospora.puleherrimaeTherp., spread by rain and wind, and invades through leaf margins or wounds.

II. Pests

The most common is whitefly, which can be controlled by spraying insecticide or drenching the roots. Taking advantage of the phototaxis of whitefly, yellow sticky insect boards coated with machine oil can be placed in the greenhouse to trap and kill them. In addition, note that whitefly generally sucks sap on the back of young leaves, and light-colored leaves are more likely to attract whitefly damage. The main pests of poinsettia are whitefly, spider mites, thrips, etc.

1. Whitefly

Adults and larvae of whitefly like dense, shaded environments. They gather on the back of upper poinsettia leaves and suck sap with piercing-sucking mouthparts, causing leaves to fade or show chlorotic spots, affecting photosynthesis, leading to poor plant growth. The honeydew excreted by the insects often causes sooty mold. Adults are attracted to yellow. Emergence begins at 6 a.m., with the greatest emergence from 7 to 8 a.m. and the lowest at night. Whitefly is most fragile as newly mobile larvae, followed by newly emerged adults, which are sensitive to pesticides, making them suitable for spray control. Whitefly generally breaks out in large numbers under high temperature and low humidity, with the peak period from late September to late November. The most suitable control period is late September, and the spraying time is from 6 to 10 a.m.

2. Spider mites

Spider mites, also known as red spiders, are common pests in greenhouses. More than 20 generations occur throughout the year. They occur severely under conditions of higher temperature, drought, and little rain. March to June and September to November are peak occurrence periods. Mites or nymphs all like to inhabit the back of old leaves. Damaged leaves have yellow spots. When checking the leaf back, insects, eggs, webs, and secretions and other debris can be found. When occurring in large numbers, they form webs and cause damage, causing plant growth to stagnate, leaves to dry up and fall off, and the plant to die.

3. Thrips

Thrips are only about 1-2 mm long and can be found causing damage on the leaves or flowers of almost all greenhouse-cultivated plants. But generally, the damage to poinsettia is not very serious. Adults and nymphs are light yellow or orange-yellow and harm plants with rasping-sucking mouthparts. Damaged parts include buds, leaves, flowers, etc., especially young leaves and new shoots, causing poor plant development. White markings on both sides of the leaf midrib can be used to identify thrips damage. Leaf damage causes white or brown markings, and in severe cases causes leaf distortion and deformity. Flowers are deformed when damaged. Yellow sticky insect paper is effective against thrips adults, but blue and white sticky insect paper works even better.

4. Whitefly

The key to controlling whitefly is to avoid the production of large populations. Whitefly adults are attracted to bright yellow, so yellow sticky insect paper is very useful for detection. There are many pesticides for controlling whitefly in various places, such as "Buprofezin" and "Gaoxiaodagongchen," etc., which can all be tried. Note here that before using a new pesticide on a large scale, a phytotoxicity test must first be done, and only after confirming that the dosage used will not cause phytotoxicity to the plants should it be used on a large scale.