Why do Clivia leaves turn yellow at the tips?

A single green leaf. When spots and yellow leaves appear on the outer leaves of a Clivia, apart from the normal physiological growth pattern, that is, the lifespan of a general leaf on the plant is about 3 years, and old leaves turn yellow, age and fall off naturally, this has no side effect on the plant and is a normal natural process of Clivia's growth and metabolism.

When spots and yellow leaves appear on new leaves and leaves that have not yet reached maturity, it is an abnormal phenomenon.

The main symptoms of leaf spot disease are: small yellow or brown round spots appear on the leaf surface, then the color of the spots gradually deepens, and the area of the rotted spots gradually expands, until the leaf or the entire plant rots away.

The main causes of leaf spot disease:

1. Applying fertilizer that has not been fully fermented. This causes bacteria to multiply in large numbers in the potting soil and produce a large amount of heat.

2. The potting soil is not changed for a long time, and disease-causing bacteria exist in the stale soil.

3. The new soil used for repotting is relatively raw and not fully fermented. It undergoes secondary fermentation in the pot.

4. The nitrogen, phosphorus and potassium in the fertilizer are unbalanced, especially when there is too little potassium fertilizer, or when the fertilizer directly contacts the roots during application.

Different methods should be adopted to prevent and thoroughly cure the above specific causes. The fertilizer applied must be fully fermented, the fertilizer concentration should be low, nitrogen, phosphorus and potassium should be balanced, and fully fermented nutrient soil should be used to replace the soil twice a year in spring and autumn; do not use raw soil. In this way, leaf spots can be eliminated.

The main symptoms of yellow leaf disease are:

1. Part of a leaf turns yellow, and the position of the yellow part is irregular.

2. The leaf tip turns yellow first and gradually spreads toward the pseudobulb.

3. The pseudobulb turns yellow first and gradually spreads toward the leaf tip.

4. The entire leaf turns yellow simultaneously from the base to the tip.

The first situation is caused by sunburn damage to the leaf surface, cold wind, bacteria spreading from places where the leaf was bitten by pests such as slugs and snails, or the wound enlarging after external injury. Yellowing that starts at the leaf tip is mainly due to root rot interrupting the nutrient supply to the leaf, so it begins to turn yellow from the leaf tip toward the pseudobulb. Or it is caused by using a large amount of strong fertilizer, raw soil, or poor soil quality. The cause of the third situation may be that pests bite the leaf at the pseudobulb, causing it to gradually spread toward the tip, or that in summer water accumulates at the pseudobulb, bacteria breed there, and the leaf turns yellow locally and gradually spreads.

It is relatively common for the entire leaf to turn yellow at the same time, and the causes are also relatively complex, mainly due to improper management. For example, poor ventilation and excessive water in summer, excessive fertilization, and problems with the roots can all cause the entire leaf to turn yellow. For preventive measures, first of all, prevent the plant from suffering root rot so that the leaves can receive sufficient nutrients; second, eliminate external injuries and prevent wounds from spreading; the amount of fertilizer applied must be well controlled, and above all avoid excessive fertilizer. In summer, do not water adult large plants at the pseudobulb, and pay attention to ventilation, cooling and strengthened management. Regularly spray sterilizing agents such as carbendazim, chlorothalonil, thiophanate-methyl and agricultural streptomycin for prevention and control, which can reduce and eliminate the occurrence of abnormal yellow leaves.