Yellow leaves on the lemon tree: causes & control

Why is my lemon tree getting yellow leaves? We explain what can be the cause of this and how to get rid of it.

Yellow leaves on the lemon tree (Citrus x limon) are always a clear sign that something is wrong with the nutrient supply or the care. The task now is to find the cause of this yellow coloration, also known as chlorosis, and to rectify it. Because over time, your lemon tree will gradually get rid of its leaves and may even die. Nevertheless, yellow leaves or a slight loss of leaves are initially no reason to panic. Once the cause is found, the tree can usually be easily cured. Even if your lemon has already lost all of its leaves, it can sprout again.

Recognize chlorosis in the lemon tree

As a rule, chlorosis in lemons and other representatives of the diamond family (Rutaceae) always looks very similar from: Due to a deficiency or breakdown of chlorophyll, the green leaf pigment, the leaves on the lemon tree change color yellow. Sometimes the whole leaf is affected, sometimes only the spaces between the leaves, while the veins remain green. Untreated chlorosis severely weakens the affected plant and in individual cases can lead to the death of the entire plant.

Causes of yellow leaves on the lemon tree

Chlorosis can have a number of causes. Every now and then individual old leaves turn yellow. But if many leaves are affected at the same time, this is a clear warning signal. It can indicate different problems:

• Waterlogging: Frequent watering is well meant, but can quickly become too much for the Mediterranean plants. If waterlogging forms, the roots begin to rot and the leaves turn yellow. Check whether the soil is very soaked or there is water in the planter.
• Dryness: Even long dry periods can lead to yellow leaves. The leaves are then often slightly curved. This type of chlorosis is rare in the lemon tree.
• Iron deficiency: Various symptoms of deficiency in the lemon tree are expressed in leaf chlorosis. Iron deficiency occurs most often in the lemon tree. The leaves and shoot tips, which are still young, turn completely yellow to almost white from the edge of the leaf towards the inside. Lemons have a high need for iron. Too high or too low a pH value in the soil binds the iron present and the plant can no longer absorb it. A pH value between 5.0 and 7.5 is ideal for the lemon tree.
• Magnesium deficiency: Yellow leaves with green veins are typical of a lack of magnesium in the lemon tree. The yellowing begins initially on the old, lower leaves. The leaf veins remain dark green in the center for a long time and stand out clearly. Acid soils with a pH value below 5 fix the magnesium in the soil. The plant then increasingly suffers from deficiency symptoms as it can no longer absorb the nutrient.

• Nitrogen deficiency: If it has not been fertilized or repotted for a long time, the lemon may lack nitrogen. Chlorosis begins on the lower, older leaves. These decrease more and more after a while. The yellow color then slowly spreads upwards towards the young leaves. A deficiency in other elements - such as zinc or molybdenum - can cause similar symptoms, but is very rare.
• Cold: Lemon trees need warmth and suffer quickly from low temperatures at the roots in winter. If these drop too much in the winter quarters, yellow leaves will form on the lemon. In this so-called winter chlorosis, the leaf veins first turn yellow. A mat or styrofoam plate under the pot shields the roots of the lemon tree from being too cold. The temperature during the winter should be around 3 to 10 ° C. Winter chlorosis resolves itself as the temperature rises.
• Wrong location: An unsuitable location can also lead to yellow leaves and leaf shedding. Drafts or a lack of light may be the cause. Especially in winter quarters, a combination of too much heat and too little light is often responsible for the discoloration of the leaves and the leaf fall. But be careful: Changing locations too often also causes stress in the plant.

Fight and avoid yellow leaves on the lemon tree

Different causes call for different measures - but how do you combat the causes of chlorosis in the lemon tree?

• With waterlogging First of all, helps to water less. Especially in cool winter quarters, when the plant hardly evaporates any water, it should only be watered very sparingly. In order to prevent waterlogging, well-drained soil, a drainage layer and a good drainage in the pot are helpful. However, repotting the plant as an immediate measure only makes sense in the spring at the beginning of the new vegetation period, as the plant growth is stimulated by repotting.
• When it is dry the plant should be adequately watered, especially during the growing season in the warm months. But first make sure that dryness is really the trigger for the yellow leaves. Often, already weakened lemon trees are only further damaged by well-intentioned watering if drought is not the actual cause.
• If there is a lack of nutrients is the right one Fertilization of the lemon tree decisive. Many nutrient deficiencies can be remedied with the help of a primarily organic liquid fertilizer like ours Plantura organic citrus & mediteranean fertilizer, fix it quickly and effectively. In addition to the main nutrients nitrogen and potassium, it also contains iron in addition to other minerals, so that the liquid fertilizer can also be used against symptoms of iron deficiency. Remember, however, that even if there are deficiency symptoms, you should no longer fertilize from August until the coming spring. The regular preventive against nutrient deficiency Repot the lemon.

Tip: Additional magnesium deficiencies can be remedied by spraying the leaves with a special magnesium fertilizer. In most cases, an adjustment of the pH value, for example by repotting in suitable soil or lightly liming, is already sufficient.

• In the case of a wrong location you should of course find a new place for your lemon tree. The lemon prefers sunny, warm and sheltered locations. Cold drafts, on the other hand, can affect the lemon tree. Therefore, think carefully about whether the planned location is really suitable, because a change of location also brings new stress with it.

Prevent chlorosis on the lemon tree

The cause of an iron deficiency and the associated chlorosis often lies in the earth. The soil from purchased potted plants is usually of poor quality and the plant should therefore be repotted to prevent chlorosis. For repotting, we recommend high-quality, loose soil with an optimal pH value of 5.5 to 6.5. It doesn't have to be special Citrus earth be. Suitable potting soil can be improved with sand, bentonite or other loosening materials and thus mixed yourself.

It is much more important that the repotting process removes as much of the old soil as possible without damaging the roots. Alternatively, you can use the Determine the pH of the soil, for example with a pH value measuring set. If the pH value is actually too high or too low, something can do it Epsom salt be lowered or carefully raised with a slight addition of lime.

Note: Citrus plants in general only need small amounts of the plant nutrient element phosphate. That is why it is practical to use low-phosphate citrus fertilizers like ours Plantura organic citrus & mediteranean fertilizer because it not only meets the needs of the beloved lemon, but also saves finite resources.

Yellow leaves and leaf fall are often associated with failure to flower. In our special article you will find out why this is the case and what other reasons may be that your Lemon tree not blooming.