Why do orchid leaves turn yellow?

There are four main reasons for the yellowing of orchid leaves: first, the basin soil is too wet or too dry, which causes root rot, root drying and shrinkage, weakening root absorption function, insufficient supply of water and nutrients, resulting in yellowing of orchid leaves; second, strong light in summer; third, diseases and insect pests The fourth is to change leaves, that is, every spring and autumn, there are always a group of three-or four-year-old plants whose half leaves wither, die and fall off, which is a normal metabolism.

In addition to the last situation which is a normal physiological phenomenon can not be avoided, the first three cases can be solved by the following measures: adjusting temperature and humidity to make the basin soil humidity suitable and air humidity increasing; strengthening shading and reducing light intensity; timely prevention and control of diseases and insect pests, especially the prevention and control of shell insects.

In addition, poor ventilation, no fertilization or replanting for a long time, unsuitable soil pH and environmental pollution are also the factors that cause the yellowing of orchid leaves, which should be solved according to different conditions. (Lin Qingde, Mu Wei)