Leaves of plants typically turn yellow for a variety of reasons, which may include nutritional deficiencies, poor drainage, compacted or damaged roots, overwatering, insufficient light and viral infections. In addition, leaves often turn yellow and drop off of house plants simply as a result of age. By investigating one possible cause at a time, it is possible to deduce the cause of yellowing plant leaves and, often, to correct the situation.
The first step to diagnosing the cause of yellowing leaves is to check the roots and drainage of the plant. If the plant isn't draining well, or if an inspection shows damage or compaction of the roots, then repotting, tilling the soil or mulching may be the solution. If poor drainage is evident, then cutting back on watering should also help the plant's health.
The most common nutritional deficiency causing yellow leaves in house plants is lack of iron. If the yellowing begins on younger leaves and gradually progresses to older leaves, chances are lack of iron is the cause. Yellowing that begins first on older leaves may be due to deficiencies in manganese, nitrogen or zinc. Testing the soil's pH level is a good first start to diagnosing these deficiencies.
If yellowing occurs only on the side of the leaves facing away from the sun, the cause may be a lack of sufficient light to those areas. If a virus is causing yellowing, the plant probably also shows other signs of ill health, including deformed leaves and flowers. In this case, there may be nothing that can be done to save the plant.Learn More
Rosemary leaves can turn yellow because of cultural issues, whiteflies, botrytis blight and spider mites. Cultural issues are a common cause of yellowing rosemary leaves and occur when the plant's root system is too large for the container that it is planted in. This problem can be corrected by replanting the rosemary in a larger container or trimming the roots.Full Answer >
Tomato plants turn yellow for several reasons, including insect infestation, viral infections, too little water and too much sun. Most of these problems affect only the plant's leaves, but the fruit can also shows signs of distress.Full Answer >
Agriculture and Rural Development of Alberta explains that yellow leaves on a cucumber plant may indicate exposure to warm, humid conditions with low light levels in the lower canopy of the plants. Yellow leaves may also indicate nitrogen deficiency, while yellow or necrotic tissue on the outside perimeter of the leaf may be caused by a rapid drop in temperature when day turns to night.Full Answer >
There are three things that make leaves on a citrus tree curl, including insect infestation, overwatering and change of climate. Insects such as the citrus leaf miner lay eggs on citrus tree leaves, and the larvae feed on the leaves.Full Answer >