The main points of sowing flowers in different seasons and the causes of yellowing of leaves of potted flowers

Potted flowers are restricted by their development. If they are poorly managed and properly maintained, they will be more prone to leaf yellowing than flowers cultivated in the open field. The causes, symptoms and remedial measures are described as follows:

First, water yellow: too much watering, basin soil water for a long time wet, resulting in a lack of oxygen in the soil, resulting in part of the fibrous root rot, so the ability to absorb water and fertilizer is weakened, causing tender leaves to become light yellow, flowers and leaves also gradually become dark yellow. After discovery, we should immediately control watering, stop fertilization, and often loosen the soil, so that the basin soil is well ventilated. If the disease is serious, it is necessary to remove the whole land from the basin and place it in the dry soil pile to make the water seep out quickly, and then replant it into the basin after the drooping branches and leaves are restored.

Second, dry yellow: too little watering, or long-term half of water or missed watering, so that the leaf water evaporation is greater than absorption, resulting in water supply falling short of demand, will also cause leaf yellowing. The "dry yellow" gradually yellowed upward from the lower leaves, withered and scorched off, and when the petiole was serious, the petiole drooped and wilted. Immediately after the discovery, move the flowerpot to a cool place, spray some water on the leaf surface, and pour a small amount of water. Later, as the stems and leaves gradually return to straight and straight, and then gradually increase the amount of water, if too much water is suddenly poured at this time, it may cause cell wall separation, protoplast damage, and cause flower death.

Third, fat yellow: excessive fertilization, especially too much nitrogen fertilizer and lack of phosphorus and potassium fertilizer, is easy to cause leaves to turn yellow, showing that the new leaves are thick, the leaves are mostly uneven, the old leaves gradually turn yellow and fall off, and when serious, the leaf tip dries up, even the whole leaf is scorched yellow. In this case, you should apply fertilizer immediately, increase the amount of water, let the fertilizer flow out of the drain hole, or pour the basin immediately, remove part of the old soil, wash the soil block with water, replace part of the new culture soil, and then plant the plant back into the basin.

Fourth, hungry yellow: insufficient fertilization, especially the lack of nitrogen fertilizer or basin soil for a long time, the lack of nitrogen nutrition in the soil, resulting in thin and yellow leaves and branches, so it is necessary to pour the pot in time, remove the plant, replace it with a larger pot, load it into a new loose and fertile culture soil, and replant it. After pouring water, put the seedlings in a half-light place to slow down. After its growth resumes, thin liquid fertilizer or compound chemical fertilizer is applied.

Fifth, alkali yellow: when planting flowers that like acid soil in the north, such as camellia, orchids, Michelia, mazi and sweet-scented osmanthus, because the soil in most areas of the north contains more saline and alkali, the above flowers and trees will gradually lose green and turn yellow due to the lack of soluble iron elements that can be absorbed by flowers after a period of time. At this time, 0.2% ferrous sulfate solution can be poured at intervals, while 0.1% potassium dihydrogen phosphate solution can be applied alternately to cure the "alkali yellow". At the same time, potassium dihydrogen phosphate also contains phosphorus and potassium elements, which is conducive to flower bud differentiation and improve flower quality.

Sixth, sour yellow: southern China is red loam, the soil is acidic or slightly acidic, magnesium in the soil is easy to lose, leaves often show old leaves, veins between the first green yellow, can be applied calcium magnesium phosphate fertilizer evergreen will suffer, causing leaves yellowing off; if the room temperature is less than 5 ℃, most flowers that like warmth and fear of cold will also suffer, leaves, flowers and fruits yellowing, dry, easy to fall off. Therefore, 0.1% to 0.3% magnesium sulfate solution should be sprayed or sprayed after entering the room. For the improvement of acid soil, attention should be paid to the application of rotten organic fertilizer, lime and a small amount of lime, which can not only neutralize the acidity of soil, but also promote the decomposition of organic fertilizer.

Seventh, bask in the yellow: flowers that like semi-shade and are afraid of high temperature and heat in summer, such as asparagus, hanging orchid, gentleman orchid, cyclamen, hanging golden bell upside down, etc., will be maintained in the place of strong light, which can easily cause tender leaf buds or leaf edge scorch or the whole leaf to turn yellow. immediately after it is found, it should be moved to a cool place with good ventilation for cultivation.

Eighth, Yin yellow: Xiguang flowers grow weak if they are kept in indoor light for a long time, the leaves become thin and yellow, do not blossom or rarely bloom. To cultivate this kind of flowers, you usually need to put them outside in the sun or half-light, and then move them indoors to watch after flowering.

Ninth, dry yellow: in winter in the north, the indoor air is dry due to heating with heating or raw coal, and some flowers that like the moist air, such as orchids and tortoise bamboos, are prone to leaf tip drying or leaf edge scorching, scorch spots and edge curling on the leaves, branches and leaves should often be sprayed with warm water close to room temperature, and a basin of fresh water should be put on the radiator or stove to increase indoor air humidity. For some precious flowers, it is best to use a plastic film cover at night, and in the cover leaves partially scorched, or even the whole plant withered. Therefore, attention should be paid to the rational application of pesticides to eliminate air pollution and avoid soil toxicity.

In addition, if the growth is too thick and afternoon spraying, it is easy to cause drug damage, causing the leaves to be withered and yellow; it is also easy to be polluted by toxic gases in the air or poisoned by toxic substances in the soil.

Finally, it should be pointed out that the leaf yellowing of potted flowers is complicated, sometimes caused by one reason, sometimes caused by several reasons. Therefore, when it is found that the leaves turn yellow, it is necessary to carefully observe the right medicine to the case in order to achieve good results. At the same time, it should also be noted that not all yellow leaf phenomena are pathological diseases, for example, when the "autumn wind sweeps the fallen leaves", deciduous flowers and trees wither yellow and die; perennial flowers wither above ground branches and leaves; flowers transplant due to temporary malnutrition, a small amount of yellow leaves fall off; individual flowers, such as Sheng branches and leaves are not trimmed for a long time, resulting in insufficient light in the inner branches, but also easy to cause leaves to turn yellow and fall off. We should pay attention to timely pruning to make it ventilated and transparent, and at the same time, we should pay attention to the appropriate application of phosphorus and potassium fertilizer to prevent the branches from growing into a basin of water.

Cold yellow: the northern winter weather is cold, if the room temperature is lower than 8 ℃ at this time, some flowers that like high temperature, such as poinsettia, variable leaf wood, leaf flower, peacock bamboo tree, flower and leaf all kinds of flowers adjust the indoor temperature according to the temperature requirements.

11. Disease and insect yellow: when flowers are infected by fungi, viruses and other pathogens, they will cause a variety of leaf spot diseases, cause local tissue necrosis of leaves, appear green macula or yellow-green mottled, or the whole leaves turn yellow and fall off. Damaged by pests such as red spiders and shell insects, chlorophyll will also cause yellow and white spots on the leaves, or yellowing and shedding of the leaves. It is necessary to spray and control in time after discovery.

Poison yellow: excessive concentration of pesticides is used in the prevention and control of flower diseases and insect pests, or when old leaves wither and yellow after sprouting new branches, such as Fusang and Magnolia in hot summer, are normal physiological phenomena, not pathological diseases.