Anyone who has it in their orchard, or at least cultivates the tree, has noticed that, in some cases, the lemon leaves yellow. This is a very common problem. First of all, because it is a much-loved tree and, therefore, very widespread. But also because it is a very delicate plant, which suffers from environmental problems, nutrient deficiencies, and diseases. And for this very reason, the reasons for the yellowing of the lemon leaves can be different.
In this article we try to give a concrete answer to this frequent question, proposing the appropriate corrective actions to solve the problem in a simple way.
The causes of yellowing of the leaves of the lemon
The yellowing of the leaves of the lemon can be due to several problems. These can be linked to the climate, the lack of certain nutrients, or, again, to specific diseases. Let’s see them in detail.
Yellowing of lemon leaves due to the climate
We all know that the ideal climate for lemon cultivation is the Mediterranean one, typical of our southern regions. Sicilian, Campania, and Calabrian lemons are among the flagships of national agriculture.
The Mediterranean climate is characterized by being mild even in the winter months, which is not always the case in the central northern regions.
One of the causes of the yellow leaves of the lemon can therefore be an excessive drop in temperatures. This induces the plant to defend itself by consuming the reserve substances present in the leaves.
If we realize that the problem is due to the cold, we don’t have to worry excessively. At the spring vegetative restart, the plant will be able to react, returning to emit new healthy and green vegetation.
The sheets of non-woven fabric
To prevent this problem we can protect the tree when temperatures drop too low. The best method is to cover the plant with a non-woven cloth.
Yellow lemon leaves due to nitrogen deficiency
When our lemon tree leaves yellow it is communicating something to us. Very often it is a lack of nutritional elements, primarily nitrogen.
We have to think like this: the lemon plant consumes a lot of energy to produce many fruits. This energy is concentrated in the leaves, which therefore tend to yellow in case of nitrogen deficiency.
Fertilization with ground lupins
Also in this case the remedy for the yellow leaves of the lemon is quite simple. In fact, it is enough to proceed with adequate fertilization, to be carried out especially at the beginning of spring. But be careful: not all lemon fertilizers are organic.
Let us remember that organic farming does not allow the use of mineral fertilizers. So, when they recommend a nitrogen-based fertilizer like urea 46, know that you are not using an organic product.
Inorganic, and especially in the home, the best organic fertilizer for lemon is the one made with ground lupins (like these).
It is a fertilizer that contains an excellent percentage of nitrogen and mineral salts. Amending the soil will help the plant to strengthen itself and, therefore, to overcome the problem of yellow leaves.
Lemon leaves yellow due to iron chlorosis
Another very frequent cause of yellowing of lemon leaves is ferric chlorosis, that is, the lack of iron in the soil. Plants are living organisms, just like people. In a human being, the lack of iron gives rise to anemic states, and in more delicate subjects to real pathological states.
The lemon is very sensitive to the lack of iron, and this is especially noticeable in cultivations on calcareous soils.
The problem is accentuated when tap water is used for irrigation, which on average contains more calcareous salts than rainwater.
When there is ferric chlorosis, the young leaves of the lemon also turn yellow, and then they start to fall. If no action is taken, the plant undergoes progressive deterioration.
Given that it is better to give rainwater to the plants, perhaps by arranging such a collection container, let’s see how to solve the problem of ferric chlorosis of the lemon.
The iron chelates
To compensate for the lack of iron in the soil, it is necessary to administer it to the plants through the iron chelates (found here). It is a product allowed in organic farming, which, in the form of chelates, makes iron readily available for plants. This also applies to soils with a high presence of active limestone.
For the dosages and times of application in fertilizing with iron chelates, always refer to the information on the product label.
Leaf yellowing due to lemon diseases
The above are the most common problems that cause the presence of yellow leaves on the lemon tree. As seen, these problems are solved quite easily, thanks to the protection and fertilization interventions.
However, there are special cases, in which yellow leaves are the symptom of a more serious problem, namely a lemon disease.
An example above all is the dry sickness of citrus fruits, which has yellow leaves among its manifestations.
In this case, it is necessary to intervene to eradicate the disease, even with drastic interventions.