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Lemon Tree Leaves Turning Yellow (Solutions That Actually Work)

The idea of having a lemon tree in your home and getting free fruit beckons many homeowners. But to get a good result, you need to have a certain amount of experience because various issues sometimes occur with the lemon tree.

Chlorosis from nutrient deficiency, sudden changes in temperature, overwatering, and scorching sun are the main causes of lemon tree leaves turning yellow. To fix the yellowing of the leaves, fertilize the lemon tree at least once a season and make sure the pH is below 7.0. Also, protect the lemon tree from the scorching sun and from overheating.

Nutrient deficiency can cause lemon tree leaves to turning yellow

Lemon tree leaves turning yellow because of chlorosis.

Lemon tree leaves turning yellow because of chlorosis.

In most cases, the yellowing of the leaves of a lemon tree is due to a lack of nutrients in the soil. This is because the fruits of this tree are quite large and require a lot of solar energy to produce. It requires large leaves, but it needs a lot of nitrogen to grow such foliage.

Very often the lemon tree is grown in containers and the nutrient content of the soil is not sufficient for the proper development of the plant. As a result, the lemon tree takes nitrogen from the old leaves to create new ones. The old leaves turn yellow but the veins remain green, this is called chlorosis.

Chlorosis can also result from a lack of magnesium, zinc, or iron. But the plant does not need much of these elements, and the amount of them in the soil is usually sufficient. The problem here is that the soil may be too alkaline and the plant can simply not assimilate these elements.

If your lemon tree leaves have turned yellow and have green veins on them, you should take a comprehensive approach to this problem. The first thing I recommend doing is checking the pH. You can do this with a soil pH meter. If your soil pH is above 7.0 you need to acidify the soil, so buy some soil acidifier at the garden store. Apply enough acidifier to make the pH of the soil about 6.5.

The second thing you need to do is apply fertilizer. It is best to choose one designed for citrus. Also, make sure that they contain enough nitrogen. It should also contain iron, magnesium, and zinc. If the fertilizer does not contain these elements, add them separately.

Remember that assimilation of the fertilizer and a change in the pH of the soil is a long-term process and you should not expect results immediately. The yellowed leaves will not turn green again, so you can remove them.

Go on, fertilize your lemon tree 2-3 times a year from the end of February. Do the second fertilization after flowering. Do not fertilize the lemon tree in late fall or winter.

Temperature changes

Lemon tree leaves turning yellow because of heat.

Lemon tree leaves turning yellow because of heat.

Next comes sudden changes in growing conditions, namely temperature fluctuations. This is true if you grow the lemon tree outside or take it outside in the summer. A lemon tree needs 70-80 °F to thrive. Small deviations from these numbers are acceptable.

If you take the pot of lemon tree outside in the spring, for example, there is a risk of cold damage. I don’t mean frostbite, because in this case, the leaves will turn brown. I mean if the temperature at night drops below 50 °F from the lemon tree definitely reacts to this. One of the possible symptoms is the yellowing of the leaves.

To avoid this, don’t take the lemon tree outside if it gets colder at night. If the leaves have already turned yellow, there is nothing you can do about it. You can water the plant once or twice more.

The second case is heatstroke. It most often happens to a potted lemon tree in the summer. In extreme heat, the pot overheats too much and the plant begins to experience discomfort and turns yellow, with the leaves collapsing. This can happen even if the soil in the pot is wet enough.

To avoid yellowing from the heat, you need to put it in a cooler place. Move the pot to the east wall of the house or a similar location, as a result, the plant should not receive direct sunlight in the middle of the day.

When growing indoors, keep the lemon tree away from heating and cooling devices.

Root rot as result of over watering

Lemon tree leaves turning yellow because of overwatering.

Lemon tree leaves turning yellow because of overwatering.

Root rot does not happen by itself, usually, the roots begin to rot because the soil is too wet. This can happen if you water the lemon tree too often or the automatic irrigation system is directed to where it is growing.

As a result of too much moisture, the roots get a lack air and start to rot. Water is not getting to the leaves and they begin to turn yellow and fall off. You will also probably smell an unpleasant odor of rot near the roots.

If the above symptoms are similar to your case, the first thing to do is to stop watering or remove the cause of overwatering. Allow the lemon tree to dry out for a few days. After that, only water it when the top 2-3 inches of soil are dry (for a potted lemon tree, 1-2 inches).

It’s also a good idea to shade the plant from the scorching sun while it’s recovering.

Next spring, replant the lemon tree in a place with less moist soil. When transplanting, make drainage and use citrus soil. Or simply add 2-3 buckets of compost to the planting hole and mix with the native soil.

If the tree is growing in a pot, change the soil to clean, pathogen-free soil. Carefully remove the dead roots, but do not shake all the soil off the roots. Also, do all this in the fall or spring, avoid transplanting in the summer heat.

Dehydration

Lemon tree leaves turning yellow because of underwatering.

Lemon tree leaves turning yellow because of underwatering.

Insufficient water can also cause yellowing of the leaves. This is especially true in the heat of summer or for a potted lemon tree. But sometimes in winter, the potting soil can also dry out quite quickly because the heating is on and you may not have time to water the plant.

All this leads to yellowing and falling leaves of the lemon tree. The symptoms are similar to overwatering because in both cases, the roots are not supplying enough water to the leaves.

The obvious solution to this issue is to water the lemon tree sufficiently. It is best if you install a soil moisture meter and monitor it constantly. Don’t let the soil dry out more than 1-2 inches if the plant is in a pot, and 3 inches if it is in the garden. You can also just feel the moisture of the soil with your fingers.

Avoid following the advice to water your lemon tree once a week or something similar. This is a sure way to lose the plant. In the heat of summer, a pot of lemon tree will dry out in a day. If you don’t water it in the evening or the next morning, it will be gone by the end of the week.

It is better to use deep watering. So water the first time with enough water to soak up the top layer. After a few minutes, water again with more water. Your task is to make sure that all parts of the root system get water.

Diseases

Lemon tree leaves turning yellow because of disease.

Lemon tree leaves turning yellow because of disease.

Another problem that often arises during the cultivation of the lemon tree is diseases. They can seriously compromise the health of the plant and the leaves can turn yellow.

Diseases are caused by pathogens, but the growing conditions are what make the development of the disease possible. The illness can be caused by a weakening of the plant as a result of over or under-watering. Also, inadequate fertilization or poor ventilation of the room increases the risk of disease for your plant.

Among plant health problems, root rot is probably the most common and can develop into crown rot. I have already told you about root rot and how to deal with it above.

Next, is a fungal disease called leaf spot. It is caused by various fungal spores that settle on the leaves and result in brown spots. The leaves will turn yellow around the spots and if there is more than one spot the leaf can turn almost completely yellow.

To deal with this you will need to remove the badly damaged leaves and spray the tree with a broad-spectrum fungicide. You can also use products containing copper. Repeat the treatment after a while.

Also, keep the plant in a well-ventilated area with plenty of sunlight and fertilize it as I recommended in chapter one.

Too much or not enough sunlight

Lemon tree leaves turning yellow because of too much sun.

Lemon tree leaves turning yellow because of too much sun.

Improper sun exposure can also cause the leaves of a lemon tree to turn yellow.

The first time this can happen is when you take the tree outside in the summer. The lemon tree is known to prefer full sun. But if it is growing in a pot and has not yet developed a root system, sunlight can have a detrimental effect. If there is too much UV light, the leaf cells will break down and the leaves will turn pale first and then yellowish-green.

In addition, if the lemon tree is suddenly moved from the room to the outdoors under direct bright sunlight, the leaves may burn. This is because less light enters the room through the windows than there is outside, so the plant may suffer when it is moved.

If the leaves have turned yellow, move it into the partial shade and let it stand there for a while. Then start slowly increasing the number of sunlight hours. This way you will find the perfect spot for your plant.

In the future don’t take the plant out of the room into the full sun right away. First, provide it with a few hours of morning sun and gradually increase the number of sun hours.

The second case is a lack of sunlight. The leaves will stretch out and sag down. Eventually, they will turn yellow and fall off.

To correct this, you have to place the lemon tree in front of a south-facing window so that it gets more light. If you don’t have that option, buy artificial light.

Key Takeaways:

  • Chlorosis can cause the yellowing of lemon tree leaves. Acidify the soil with compost and fertilize with a citrus fertilizer.
  • Abrupt changes in temperature or extreme heat can cause potted lemon tree leaves to turn yellow. Move the plant to the shade for the duration of the heat.
  • Too wet and too dry soil can cause yellowing of the leaves. Water the lemon tree only when the soil is 2 inches dry.
  • Diseases are a common cause of leaf yellowing. Spray the lemon tree with fungicide.