The fruits of the lemon tree are a source of vitamins and other beneficial substances. It is for this reason that many gardeners strive to grow lemons in their gardens. But it is very unpleasant when something bad happens to your tree.
Too much or not enough water, improper feeding, and extreme heat are the main causes of curling lemon tree leaves. To fix the curling, water the lemon tree when the ground is 2 to 3 inches dry, fertilize the plant at least twice a season with a fertilizer that contains nitrogen, phosphorus, and potassium. Also, treat the lemon tree for pests and diseases and provide partial shade in the heat.
Dehydration can cause Lemon tree leaves curling
Lemon tree leaves curled because of dehydration.
Lack of water in the ground for a long time can cause the curling of the leaves of the lemon tree. If there is a lack of moisture, the plant tries to reduce the evaporation area by curling the leaves upward.
Also, the color of the leaves may change to a pale green. In severe drought and heat, the leaves may begin to shrivel at the edge and tips.
Hot, dry winds are even more destructive. In windy summers, the ground can dry out in a few days. If you are growing a lemon tree in a container, the potting substrate can dry out in one day if the plant is placed in full sun.
The obvious solution to this problem is to give the plant enough water. I recommend watering a lemon tree that grows in the garden when the substrate is 2 to 3 inches dry. As for a potted lemon tree, it is best that the soil in the pot does not dry out more than 1 inch. You can check how wet the soil is with your fingers or use a moisture meter and that is more convenient.
Watering technique is also an important aspect. Water the lemon tree with a large amount of water and the soil in the root zone should be sufficiently moist. But avoid overwatering. If the plant is growing in a pot, pour as much water as is needed for the excess to flow out through the drainage holes.
If there is strong sun and wind, move the potted lemon tree to a place sheltered from the wind and with a little shade. When the heat subsides, return the plant to its previous location.
Root rot as a result of overwatering
Lemon tree leaves curled because of root rot.
Overwatering is one of the most common sources of problems with most plants. Wet soil over a long period of time will cause oxygen deprivation of the root system and root rot. As a result, the supply of water to the leaves will be disrupted.
The leaves will begin to turn slightly yellow and curl downward. Also, the tips of the leaves may shrivel up and turn brown. If there are fruits on the tree, they may also begin to rot.
Overwatering occurs when the tree receives water frequently, even when it does not need it. Also, sometimes in the spring in rainy weather, the roots may begin to rot due to excessive rainfall in the soil. And lastly, some lemon tree owners water several times a day during a heatwave. They do this to save the plant from temperature stress instead of moving it into the shade.
The first thing to do to save the lemon tree from overwatering is to reduce the frequency of watering. As I said before, only water the lemon tree when the soil is 2 to 3 inches dry, but not before. The plant will eventually recover if the root rot has not spread too much.
The potted lemon tree can be replanted in clean, drained soil. But don’t shake all the soil off the roots, just the part where the roots are rotten. Remove any dead roots. Be sure to use a pot with drainage holes.
After transplanting, move the lemon tree container to full shade. When you see the plant recovering, accustom it to the sun gradually.
Poor soil
Soil plays an important role in the life of all plants. Since the lemon tree is a fruit tree, it needs very nutritious soil. Poor soil will not only lead to poor fruiting but also leaf problems.
If for some reason the nutrients do not get to the roots, the leaves will not be able to photosynthesize and will turn yellow and curl. One particular symptom of a lack of nutrients is a yellowing of the leaf with green veins and simultaneous outward curling. This is called chlorosis.
Lemon tree leaves curled because of chlorosis.
The first most common case of nutrient deficiency is growing a lemon tree in a pot. The fact is that the amount of soil in the pot is limited and over time the water washes all the minerals out of it. The roots can not grow deep into the soil to get access to new trace elements and as a result, the leaves are deformed.
The second case is when the soil is too alkaline (pH<7.3). In such a soil the plant is not able to absorb all the necessary substances, namely nitrogen, and magnesium. These two elements are responsible for photosynthesis and the creation of green leaves. As a result, the lemon tree develops chlorosis.
The first thing you need to do to help your plant is to check the soil pH. And if it is high, you need to acidify it to about pH 6.5. You can find both soil pH tests and acidifiers in garden stores.
Or you can go the other way and put multi-purpose compost in the soil around the roots of the lemon tree. Also, mulch the area around the trunk with compost, but do not cover the trunk with mulch. The compost will acidify the soil and make it more nutritious.
Second, apply a citrus fertilizer. There are many good products on the market, but make sure the fertilizer contains nitrogen, phosphorus, potassium, and magnesium. Personally, I prefer slow-release pellets because they are much easier to handle.
Next, fertilize the lemon tree at least twice a year. The first time do it in spring when the plant is just waking up from its winter dormancy. The second time apply fertilizer in mid-summer to help the tree form juicy fruit. I do not recommend fertilizing the lemon tree over the winter.
Insects
Lemon tree leaves curled because of leaf miner.
Insects are also a common cause of curling lemon leaves. First of all, the aphids should be mentioned here. These insects are very widespread and should you let your guard down a bit, they will immediately occupy young leaves.
As a result of their activity, the leaves begin to curl upward. Aphids are usually found on the underside of leaves and feed on their sap. Ants, which feed on the sweet secretions of the aphids, also help to spread them.
Getting rid of aphids is quite easy, if there are not too many insects, wash them off with a stream of water from a hose. If this does not help, spray the lemon tree with Neem oil.
The second type of pests is leafminers. These insects live in the leaf blade and make their way through it. Their activity is noticeable by a specific pattern on the leaves, which you can see in the photo. The leaves curl chaotically at the points of damage.
If a leafminer has damaged one leaf, tear it off and throw it away or destroy it. If the spread of this pest is significant, spray the plant with Neem oil or pesticide.
The last pest that causes significant damage is the spider mite. These creatures settle on the underside of the leaf and suck on it. As a result, the leaves curl down.
It is difficult to see the mites with the naked eye; you are better off using a magnifying glass. If you see microscopic bugs that are white, reddish, or brownish in color, they could be mites. Their peculiarity is a thin web around their habitat.
To rid your plant of mites you need to mist the leaves regularly. This practice is quite effective because mites do not like a wet environment. But fogging doesn’t always solve the problem, if the mites don’t go away you need to spray the leaves with acaricide. This is a specific product designed specifically against mites and is easy to find in most garden stores.
Extreme heat
Lemon tree leaves curled because of extreme heat.
The lemon tree is a heat-loving plant; it thrives in normal summer temperatures. But if the weather is too hot or too cold during the growing season, the leaves may become damaged. One of the signs of such damage is curling leaves.
The most common time a lemon tree gets temperature stress is during the heat of the summer. If the tree grows in a pot that is placed in full sun all day, the ground can get very hot. As a result, defense mechanisms kick in and the leaves curl inward and turn yellow.
The scorching sun will make the situation even worse by drying out the leaves and they may even become crispy around the edges.
This is true not only for the potted lemon tree but also for newly planted plants. Young trees do not yet have a full root system and can easily suffer from overheating.
During extreme heat, owners increase the frequency of watering. This unfortunately doesn’t solve the problem completely but instead can lead to root rot.
I recommend moving the pot with the lemon tree into the partial shade. The plant should only get direct sunlight in the morning and evening. Increase watering slightly and don’t let the soil dry out more than 1 inch.
When the heat is gone, return to normal watering as I recommended above and move the lemon tree to its original location.
If the lemon tree is growing in the garden, place a shade over it for the duration of the heat.
To prevent the soil from overheating, mulch the surface with compost. The layer of mulch should be 2 inches. Do not mulch too close to the trunk of the tree.
Lemon tree diseases
Lemon tree leaves curled because of citrus scab.
The first disease that causes the curling of the leaves of a lemon tree is a bacterial blast. This is quite a serious threat to your plant. It can affect almost all parts of the tree.
Signs of the presence of bacterial blast are cracked bark on the branches. Sap can ooze through the cracks. The young shoots turn black and the leaves curl and turn red. After a while, the leaves fall off.
To help the plant heal, remove all affected branches and leaves. Then spray the tree with copper-based fungicide. You may have to repeat the spraying several times. Of course, after such treatment, the fruit will become unfit for consumption.
The second disease is a citrus scab. Its characteristic feature is white tubercles on the fruits and leaves of a lemon tree. Leaves curl and turn yellow in the affected areas.
In fact, it is a rather complicated disease that requires complex treatment. Multiple sprays of copper fungicide, sulfur, and other products are used to combat it. If your lemon tree shows signs of this disease, you should contact a professional to treat it.