Why Are The Leaves Turning Yellow On My Lemon Tree

It is common to wonder why the leaves of one’s lemon tree are turning yellow; such yellowing of the leaves can have multiple causes and understanding the cause is important for identifying the appropriate treatment. Contraction of objects or droplets on the surface of the leaves, likely due to environmental factors like water vapor, can be the cause of yellowing. Additionally, this could be due to a fungus – either fungal or bacterial – that has been thriving in the soil. In some cases, an insect infestation such as insects feeding on the sap can also be the source of the yellowing.

Beyond physical causes, there may also be nutritional deficiencies causing the problem. Such factors can range from improper pH levels, deficiencies of certain nutrients such as iron, zinc, and magnesium, or even overwatering. Without adequate nutrition, the leaves of a lemon tree may be more prone to turning yellow. Furthermore, if the tree has extended periods of drought without water, yellowing may occur. It is also possible that the tree has infected by pests such as citrus blackfly.

Aside from physical and nutrient-related causes, yellowing may also be triggered by the age of the tree. Older trees are more likely to experience yellowing since their leaves tend to become less viable with time, or the tree may not be able to transport water to the leaves sufficiently. It is also possible that the tree has been over-pruned, leading to a lack of nutrients and overall health of the leaves causing them to turn yellow. Finally, too much direct sunlight can also cause the leaves to yellow.

Nutrient Deficiencies

Nutrient deficiencies can be a common cause for the yellowing of a lemon tree’s leaves. Such deficiencies can be caused by soil composition that does not have enough of the required nutrients for the tree, as well as significant water or temperature changes, or even excessive amounts of fertilizer applied to the planting site. If a plant does not receive the proper nutrition, it cannot produce adequate amounts of chlorophyll, which can then result in yellowing. For example, iron deficiency can reduce the ability of the tree to produce sufficient chlorophyll.

Testing the pH level of the soil and adding the suitable fertilizer will help to diagnose and treat deficiencies of nutrients. Furthermore, adding an iron rich fertilizer can help with photosynthesis, which can help to prevent further chlorophyll loss on the leaves. Additionally, applying certain types of mulches that are high in organic matter can help with water retention. Mulching can help to provide more nutrients and improve soil quality, aiding the growth of the lemon tree and preventing further yellowing.

In addition, misting and providing additional humidity to the plant can help with the absorption of certain nutrients, as well as providing a better access to water for the plant. Finally, keeping the area where the plant is located free of pests can also help to reduce the yellowing of the leaves.


Overwatering can lead to the yellowing of lemon tree leaves due to a lack of oxygen around the root system. Without proper oxygen availability, the root system of the plant is not able to function properly, resulting in chlorosis. When plants are overwatered, the water does not easily penetrate the soil, and instead lingers near the surface for an extended period of time. This results in less oxygen, and a greater chance of fungal disease.

Identifying and treating overwatering is important, as the root system of the plant can begin to rot and succumb to fungal diseases without proper treatment. The first step is to evaluate the amount of water the plant receives; if it is excessive, it should be reduced. Other signs of too much water could include an increasing level of water in the soil, algae growth, or pooling water on the surface of the soil. One can also simply reduce the amount of water the plant receives, and instead wait until it is dry before watering again.

If the issue is caused by poor drainage, improved soil aeration or mulching can help to decrease the drainage problem. One can also use a drainage on the soil surface to ensure that water does not accumulate in the soil. Finally, if fungal disease is detected, one should add amendments or organic material to the soil to boost the organic life of the soil.

Insect Infestations

Insect infestations can also be the cause of yellowing in lemon tree leaves. Insects like thrips, whiteflies, and mites can feed on the sap of the leaves, resulting in reduced growth and yellowing. Such infestations can be identified by physical observation of the leaves; leaves will contain tiny insects on them, or holes or patches in the leaves. The leaves may also be covered with a black and sticky substance.

To treat the problem, one can remove the insects manually by using a damp cloth, while more severe infestations may require the use of insecticides. Homemade insecticides such as spraying a solution of garlic and soap on the leaves can also work. One can also apply Systemic Insecticides that can penetrate the leaves and work systemically, as well as horticultural oils or neem oil to get rid of the insects. Furthermore, introducing beneficial insects such as ladybugs or lacewings can help to keep the population of the pest insects in check.

Direct Sunlight

Even though a lemon tree needs lots of sunlight to grow and thrive, too much direct sunlight can cause the leaves to turn yellow. When leaves are exposed to too much direct sun, their internal temperatures are raised and the cells are damaged. Once the cells are damages, they will turn yellow and may eventually fall off the tree. Therefore, it is important to identify how much direct sunlight the tree receives, and adjust accordingly.

Direct sunlight can be reduced by providing additional shade to the tree, such as installing shade cloth over it. Controlling the intensity, duration, and direction of sunlight all play a role in protecting the tree from an overload of direct sun. Additionally, one can prune the top of the tree to reduce the amount of exposed leaves, as well as trim back the branches to provide additional air circulation.

In addition, using a protective covering such as a tree wrap can also reduce the amount of direct sunlight the tree receives. Such wraps should be applied differently depending on the size of the tree; wrapping a tree too tightly can cause serious damage to the trunk. Furthermore, mulching around the base of the tree can also help to provide additional protection from the sun, while allowing water and oxygen to penetrate the soil.

Environment Factors

Environmental factors can also cause the yellowing of leaves on a lemon tree. Such factors can range from low temperatures, high winds, and improper watering or humidity. Low temperatures can cause the roots to become dormant, resulting in stagnation of nutrient and water uptake, which can lead to yellowing of the leaves. High winds, on the other hand, can dry out the leaves, causing their color to lighten or fade.

In terms of water or humidity, a lemon tree needs careful and constant monitoring. Drought conditions can lead to yellowing of the leaves due to the lack of water. The tree should be watered enough to keep the soil moist, but not drenched as this can also lead to root rot and yellowing. Furthermore, humidity can also cause yellowing; high humidity can lead to fungal diseases, while extremely low humidity can cause the leaves to dry out and turn yellow.

In order to prevent these environmental factors from causing yellowing of the leaves, several steps can be taken. Monitoring the temperature of the area and provision of shade, if needed, will help to prevent low temperatures. For high winds, binding the branches to provide some stability can be useful, and sheltering the tree from direct wind can also help. Proper irrigation and draining of water will help to keep the ground at a suitable water level, while increased humidity around the tree can help to reduce drying of the leaves.

Gordon Wesson is an environmentalist and author who lives in the Pacific Northwest. He has been writing for many years about topics related to trees, the environment, and sustainability. In particular, he is passionate about educating people on the importance of living in harmony with the environment and preserving natural spaces. He often speaks at conferences and events around the country to share his knowledge with others. His dedication to protecting our planet makes him one of the leading voices in his field today.

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