What causes orange leaves?

What caused the yellow leaves of orchids? Please give an introduction and solutions to the main factors causing orchid yellow leaves for reference: yellow leaves caused by excessive fertilization: excessive fertilization, especially excessive nitrogen fertilizer and lack of phosphorus and potassium fertilizer, it is easy to cause the leaves to turn yellow. it is characterized by the thickening of new leaves, most of the leaves are rugged, the old leaves gradually turn yellow and fall off, and when the leaf tip dries up seriously, 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. Yellow leaves caused by lack of fertilizer: insufficient fertilization, especially long-term lack of nitrogen fertilizer or basin soil, lack of nitrogen nutrition in the soil, resulting in thin and yellow leaves and branches, so it is necessary to pour the plant out in time, 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 semi-shady place to slow down the seedlings. After its growth resumes, thin liquid fertilizer or compound chemical fertilizer is applied. Yellow leaves caused by excessive saline-alkali content in soil: when planting flowers that like acid soil in the north, such as camellia, orchid, Michelia, mazi and sweet-scented osmanthus, because the soil in most areas of the north contains more salt and alkali, after a period of time, 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. 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. Yellow leaves caused by soil partial acidity: red loam in southern China, the soil is acidic or slightly acidic, magnesium in the soil is easy to lose, leaves often show old leaves, the veins of leaves are green and yellowing first, calcium magnesium phosphate fertilizer or 0.1% to 0.3% magnesium sulfate solution can be applied. 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. Click to get more orchid planting techniques click to get more flower planting techniques