If only a few leaves turn yellow and fall, no need to panic, these are normal steps in the process of leaf renewal. The older ones turn yellow and fall to make way for young leaves, including houseplants or evergreen shrubs. If the yellowing spreads, however, the issue is looked at more closely.
First step, make sure the leaves do not turn yellow to cause of illness. If this is the case, the yellowing is in principle accompanied by other symptoms: stains, deformations, webs, presence of insects or fungi ... The affected leaves are carefully examined in order to eliminate the potential risks, and hopefully well, we move on.
One of the first causes of yellowing leaves is just an excess of watering, especially for indoor potted plants in poorly drained soil. Most plants hate macerating in water! The rule is simple, you do not water before the soil is dry at the base of the plant. If the soil is too wet, we plan to repot the plant in a pot with a drain and a cup, without allowing the water to stagnate in the cup, or even on a background of gravel or marbles. clays in the pot to improve drainage. Be careful, however, a lack of water can also cause the leaves to turn yellow. If the soil is dry and the leaves withered, we water without excess and we observe.
Second cause of frequent yellowing, a poorly exposed plant, and not only in terms of brightness. Most plants hate drafts and large differences in temperature. Placed in front of a regularly open window or in line with the front door, for example, some indoor plants start to yellow to express their dissatisfaction. As for the sun, some plants need a lot of sunshine, others do not, some do not support direct light, others do. The solution ? We learn about the needs of the plant according to its species and then move it if necessary.
Amend the earth
Last option? The soil, or the substrate, does not provide the plant with the nutrients it needs. Several deficiencies are possible, the most common being chlorosis, iron deficiency. In this case, the veins remain green and the yellowing of the leaves begins at their edges. Whatever the deficiency, it must be identified before enriching the soil with an amendment or a fertilizer. And to identify it, we do research according to the symptoms on the leaves or we bring a leaf, or even the plant in a garden center!