There are several reasons for yellow leaves:
One, water yellow. As a result of long-term watering caused by leaf yellow, manifested in the young leaves yellowish luster, the old leaves are not obvious changes, the root is small, yellowish-green, the new end of the shriveling does not grow, should be restrained from watering, heavy pots can be taken off the pot, put in the shade of the sun to dry the soil and then re-potting.
Two, drought yellow. Due to lack of water or low watering caused by leaf yellowing. The old leaves from the bottom up yellowing off, but the new leaves generally grow normally. Should be appropriate to increase the amount of watering and watering times.
Three, fertilizer yellow. Due to too much fertilizer or concentration is too large, the top of the new leaves appeared dry brown, old leaves tip dry scorched yellow and fall off, the general surface of the leaves, although fat and glossy, but most of the bumpy. Should stop watering fertilizer or use water to wash the fertilizer.
Four, lack of fertilizer yellow. Potted flowers for a long time only watering without fertilizer, or many years without changing pots, roots and whiskers into a ball, the plant can not get fertilizer, so that the leaves yellow, in addition to timely change the pot, usually should be thin fertilizer. Such as bamboos often get iron deficiency yellow leaves. Woody flowers in the greenhouse, due to changes in soil fertility conditions, often yellow leaf phenomenon, characterized by young leaves obviously, old leaves lighter, yellow leaf flesh, green veins, and the formation of a typical network; can be applied to solve the ferrous sulphate solution, the method is: 7 cake fertilizer, ferrous sulphate 5 parts, 200 parts of water into a doubled liquid watering.
Five, burning yellow. Shady and wet pot flowers and foliage plants, such as hanging orchids, Nelumbo nucifera, a leaf orchid, yuzhan bamboo taro, such as by strong direct sunlight, the leaves often appear yellow tip, should be put in the shade.
Six, alkali yellow. Like acidic soil flowers, such as azalea mast camellia, osmanthus white orchid, such as potting soil or water alkali, often caused by green leaves to yellow, or even fall off, in addition to the acidic nutrient soil carrier cultivation, can be used to use alum fertilizer water or 0. 2% -0. 5% ferrous sulfate aqueous solution spraying, both the leaves can be made from yellow to green.
Seven, hot and humid yellow. Some intolerance of high temperature, high humidity flowers, due to the summer heat, poor ventilation storm, avoiding improper shade caused by yellowing. Such as inverted golden bell, azalea in the hot and humid environment of this phenomenon, pay attention to ventilation and cooling, and potting soil can not be too warm.
Eight, albino yellow. Flowers often insufficient light, chlorophyll in the leaves to reduce the green leaves gradually disappear, showing albino disease, you can move the plant to a sunny place, so that the leaves slowly become green.
Nine, low temperature yellow. In the cold winter, such as indoor temperature is low, some of the flowers afraid of cold, such as white orchids, Guangdong wannianqing, a red, the leaves will also turn yellow, fall off. In addition, by the pests and diseases of flowers can also cause yellow leaves and fall off. If the lower part of the plant has a few leaves turn yellow and fall off, it is a normal phenomenon.