Are your lemon tree leaves curling, and you’re not sure why? I know, curled leaves can be a disheartening sight for us citrus growers! If the leaves are curling, then this can impact fruiting, so we need to address the problem with a sense of urgency!
I work in a garden center and have to diagnose problems with plants. In my experience, most of the time, lemon tree leaves curl up as a reaction to drought.
You may be thinking, “But I am watering my lemon trees every week; why are my lemon tree leaves still curling?”…However, excess wind, low humidity, and watering too lightly sap moisture from the leaves, causing them to curl to conserve moisture.
I should also highlight that Aphid infestations feed on the sap of emerging leaves, which causes leaves to curl, which is something you see in the Spring.
Whilst drought stress is the most common reason for leaves curling on your lemon tree it isn’t the only reason…nutrient-deficient soil, transplant shock from moving lemon trees indoors, and even overwatering can cause leaves to curl often with yellowing of leaves and leaf drop.
The good news is I’ve diagnosed all the problems I talk about in this article and share with you all the steps required to save your curled lemon tree leaves and restore their appearance.
Keep reading to identify the causes of your curling lemon tree leaves, how to prevent it, and how to revive it…
Underwatering is the Most Common Cause of Curling Leaves
Whenever someone tells me their lemon tree leaves are curling downwards, I check the soil to see if it is moist or damp. This is because leaves that have a shriveled and curled appearance most often indicate that the lemon tree is suffering from drought stress.
Lemon trees actually prefer the soil to be on the dryer side compared to a lot of fruit trees but problems occur when the soil dries out completely or there is too much wind that saps moisture from the leaves.
Pro tip: So, I Iook for clues to see if the soil is too dry…first I pick up the pot (if it’s not too heavy!). If the soil is completely dry, then the pot is going to feel much lighter then you were expecting. I also look to see if the soil has shrunk away from the side of the pot (which it often does when its completely dry).
But we should consider that not watering often enough isn’t the only reason for lemon tree leaves curl…
- Watering too lightly. Lemon trees prefer the top two inches of the soil to dry out between bouts of watering, followed by a generous soak, around once per week. If the lemon tree is watered too lightly, the water does not infiltrate the soil and reach the roots, which causes the leaves to curl.
- Pots heat dry out quicker. The soil in pots dries out a lot quicker than the soil in garden borders. Pots have less capacity for soil and, therefore, less capacity for moisture. Also, lemon trees require full sun, which can further exacerbate the drying of pots and cause drought.
- Excess wind. Lemon trees should have some protection from wind as excess wind increases moisture loss from the leaves which is one of the more rapid causes of the leaves curling.
How to Revive Lemon Trees with Curling Leaves due to Drought
Lemon Trees with curling leaves that have suffered drought can be revived if you adjust some conditions.
- Try to shelter the tree from direct wind. With potted trees, this may be as simple as moving the tree to an area with a natural wind break, such as shelter from other trees or fences. Be careful not to deprive your lemon tree of sunlight when moving it to more shelter. For lemon trees planted in garden soil, try to form a wind break with other plants to buffer the worst of the winds. I personally like to use bamboo for this as bamboo tolerates wind well and provides a wind break all year round!
- Mist the lemon tree’s shriveled leaves with a sprayer to increase the humidity of the micro-climate and mitigate water loss from the leaves. Spray the leaves twice a day whilst the lemon tree recovers.
- Use a soaker hose for lemon trees planted in the garden. I have left a soaker hose on for several hours to saturate the ground if it has. been really dry. It is important to be generous with watering after drought because excess heat and sun bake the soil hard so that water runs off the surface rather than infiltrating to reach the roots, so ensure that you give the tree a generous soak. I find that a soaker hose is an effective method of countering dry, hard soil that repels water from the surface (and away from the rootball).
- Increase the frequency of watering for lemon trees in pots. Potted plants dry out quicker, particularly in full sun. Lemon trees prefer the soil to be somewhat dry between bouts of watering, but too much sun and heat can cause drought stress. Water as soon as the top two inches of the soil are dry, which can be twice a week or more in summer.
For potted lemon trees suffering from drought, it can be beneficial to submerge the entire pot in water. But how do you do this? What I’ve done whilst at the garden center is fill a wheelbarrow with water and sit the lemon tree’s pot in there for 20 minutes or so.
The reason why I favor submerging the pot in water like this is because it allows the moisture to reach the roots without running off the surface of the dry soil and down the side of the pot without reaching the roots. When you lift it back out of the wheelbarrow, it is going to feel a lot heavier (I can tell you from experience!), but this is a good sign! A well-hydrated rootball is a heavy rootball, so get someone to help you lift it…
Once the lemon tree has a good watering and the leaves have been sprayed regularly, the leaves should recover from their curled appearance over the following week. Honestly I have seen curled leaves restore their appearance in as a little as 1 day.
If it is a hot day I recommend temporarily shading the lemon tree, so that it does not have to contend with blazing sunshine whilst recovering from drought.
I’ve noticed anecdotally that sometimes the leaves do temporarily wilt if the temperature is particularly hot during the day, and the leaves perk back up at night, which is simply a reason for high temperatures and nothing to worry about.
My Best Tip: Is your potting soil drying out very quickly and causing your leaves to wilt? Is your lemon tree planted in a clay or terracotta pot? These types of pots have a porous structure, which means the soil can dry out too quickly on hot days. My solution? I repot struggling lemon trees with curling leaves into plastic or ceramic pots…why? Because these materials are impermeable (which means they retain moisture) therefore, your lemon tree won’t dry out as quickly so that the roots can access the moisture they need, which prevents the leaves from curling.
(Read my article on how to water lemon trees to learn how to establish the optimal watering frequency for your climate).
Why Are My Indoor Lemon Tree Leaves Curling?
As I’m sure you know, lemon trees are tropical plants that are not cold-hardy, and therefore, lots of people grow them in pots and take their trees indoors over Winter for protection from frost.
However, there are some specific conditions indoors that tend to cause a lemon tree’s leaves to curl and even drop off that are unique to an indoor environment that we need to consider…
The conditions that cause leaf curl for indoor lemon trees are:
- Dryer air with low humidity. Lemon trees are native to tropical climates and prefer some humidity. Have you got the heating on? Indoors, the lemon tree leaves have to contend with air currents from air-con, forced air, and radiators, which sap the moisture from the leaves. The lemon tree reacts by curling its leaves to conserve moisture. This often results in a lemon tree losing some of its leaves.
- Sources of heat causing fluctuating temperatures. When we are indoors in Winter we often turn on the heating at home in the evenings. This is at odds with the daily cycle of temperature change that a lemon tree experiences when outdoors which causes stress that manifests in curled leaves. I’ve noticed that the heat also increases evaporation from the soil much more quickly, which dries the plant out and results in shriveled leaves.
- Less light indoors. Lemon trees prefer full sun, so they often suffer from shock, which reacts to lower light levels indoors and causes stress.
- Transplant shock. Lemon tree leaves can curl as a reaction to a sudden change in environment as there is a significant contrast between the conditions of the outdoors and your house. It is the drastic and sudden contrast in conditions, such as temperature, that is responsible for the leaves curling. Whether it is a sudden increase or decrease in temperature, it is primarily the instability of temperature that is your lemon tree’s greatest adversary, as both can result in curling leaves that drop off.
How to Revive an Indoor Lemon Tree with Curling Leaves
Indoor potted lemon trees can recover even if some of the leaves are starting to drop or turn yellow. I’ve done this myself, and I found that the key is to address the moisture balance and mitigate the shock of being moved indoors.
- Spray the leaves with a mist sprayer or use a humidifer. This is one of the most effective ways to revive curled leaves as it effectively increases the humidity to replicate the preferred conditions of the lemon tree. You can either Spray with water as frequently as twice per day to ensure the leaves stay moist whilst they acclimate to your home and to mitigate water loss from the leaves or use a humidifier (which I find much easier!)
- Ensure that the lemon tree is not in any direct airflow from air conditioning or forced air. The lemon tree should be in a sunny window and out of the way of air currents. I place mine in a nice sunny south-facing window.
- Increase the frequency of watering. Lemon trees become habituated to a watering frequency outdoors, but their demand for water increases when they are brought indoors, which causes the leaves to curl as a sign of stress. As we discussed, lemon trees prefer the top two inches of the soil to dry out between bouts of watering in the Winter because of the reduced rate of growth, however, I find that lots of heat indoors can drive evaporation and cause the pot to dry out more quickly. Monitor soil moisture regularly, and as soon as the top two inches of the soil are dry, give the tree a good soak.
- Give your lemon tree time to acclimate to indoors. The shock of being moved indoors causes stress to the lemon tree but as long as it is located in a sunny window, watered according to its conditions, and the leaves are sprayed regularly then it should revive.
What I’ve found whenever I have done this is that some leaves can drop off after they have curled up as this is the lemon tree’s way of conserving moisture.
I want to reassure not worry, if this happens as new leaves emerge in the Spring in reaction to more hours of light if the tree is cared for properly. It is true that lemon trees are evergreen but in reality the lemon tree loses some leaves each year. When this happens I usually observe new leaves growing in the Spring.
Top Tip: What is the best way to increase humidity for lemon trees? I switched from misting the leaves every year when brought my tree indoors to using a humidifier. What I noticed was that not only did the leaves not curl, but I also had significantly fewer leaves falling off! I think a humidifier is a much more effective way of recreating the humidity that lemon trees love!
(Leaves can drop from lemon trees for several different reasons so I wrote another article on what causes lemon trees to lose their leaves and how to save it).
Are You Watering Too Much? (Overwatering Causes Lemon Tree Leaves to Curl and Droop)
As we have talked about Lemon trees prefer dryer soil conditions than most fruit trees and are susceptible to overwatering, which can also cause leaves to curl as a sign of stress. (Yes, I know it’s confusing, the leaves can curl due to both overwatering and underwatering, we just have to find that happy medium!)
Are there any observable differences between an underwatered and overwatered lemon tree? Typically curling leaves caused by drought also look shriveled in appearance whereas curling leaves from over watering can lose their green color and turn slightly yellow.
(Yellow leaves on your lemon tree can indicate several problems, so I wrote another article on what causes lemon tree leaves to turn yellow).
We need to remember that our lemon trees require well-draining soil and prefer the top two inches of soil to be somewhat dry between bouts of watering.
I must highlight that Overwatering is not the only reason for your Lemon tree leaves curling…
- Watered too frequently so that the soil is constantly moist. If the soil is damp, the leaves tend to curl and turn yellow, which is a sign of stress. Damp soil also promotes the conditions for fungal diseases such as root rot, which can kill the lemon tree.
- Slow-draining soils. Lemon trees do not grow well in boggy areas or heavy clay that retain lots of water. They naturally grow in well-draining soil with a high organic content and perhaps some inorganic material such as grit for improved drainage. Slow-draining soils mimic the effects of overwatering causing the leaves to curl, turn yellow, and risk root rot.
- Pots with drainage holes in the base. Some decorative pots do not have proper drainage holes in the base which causes the soil to become saturated causing the leaves to curl, turn yellow, and potentially drop off as a sign of stress.
- Trays underneath pots of indoor lemon trees. Trays under pots prevent excess water escaping the pot and cause the soil to become boggy which causes stress to your lemon tree.
How to Revive Lemon Trees with Leaves Curling due to Overwatering
- Scale back the watering. Only water your lemon tree when the top two inches of soil is dry. Typically, in my experience, this takes my lemon trees about a week to dry, but you should determine how often to water your lemon tree according to your climate and weather conditions. Wait till the soil is dry to a finger’s depth, and then give the lemon tree a generous soak.
- Lemon trees should be planted in well-draining soils. If your tree is in a boggy area then ideally you should transplant it to an area of the garden that is more well-draining or the lemon tree is likely to die back. A good potting mix or soil recipe for lemon tree growing is 1/3 multipurpose compost, 1/3 garden compost, and 1/3 horticultural grit, sand, or perlite. This soil mix replicates the soil conditions of the lemon tree’s natural environment and provides a good balance of soil nutrients and good drainage.
- Potted lemon trees should be grown in pots with good drainage. If your pot does not have drainage holes in the base then transfer to another pot as a matter of urgency as the curling leaves can turn yellow and the plant can die.
- Trays underneath pots should be emptied of water regularly. Whilst trays under pots can be important to prevent watering spilling from your indoor lemon tree there should not be watering pooling underneath the pot for long periods.
With more favorable drainage and good watering practices, the soil around the roots of your lemon tree can dry out somewhat between bouts of watering.
This creates the perfect balance of moisture in the soil for lemon trees and allows the plant to recover.
You should start to see improvement in the curling leaves in the following weeks.
I honestly think the most important factor in preventing the leaves from curling (due to overwatering) is the addition of grit and perlite into the soil or potting mix.
Top Tip: Are you in a climate of high rainfall? Then, plant your lemon tree in a pot (better drainage characteristics) and add a little more grit to the potting mix (up to 40% by volume to ensure good drainage). This is going to go a long way to prevent overwatering and preventing the leaves from curling.
If you have a boggy garden, then I would always recommend that you pot regardless, as it is very difficult to amend the soil so that it is sufficiently well-draining for a citrus tree.
In climates with really heavy rainfall, I would also recommend planting your citrus trees in clay or terracotta pots. As we discussed earlier in this article, clay and terracotta are porous, which allows the soil to dry out more evenly. This is a great way to mitigate the effects of heavy rainfall.
However if the soil remains too damp then the lemon tree is likely to develop the fungal disease root rot causing the leaves to curl, turn yellow, and drop off and the plant to die back, hence the importance of knowing how to water properly.
(Read my article, How to Revive a Dying Lemon Tree).
Nutrient Deficient Soil causes Lemon Tree Leaves to Curl Up
As I’m sure you all know, Lemon trees are heavy feeders and require regular fertilizer applications in the Spring and Summer to meet their nutritional requirements and to produce the best fruit and flowers.
But what are the symptoms of a nutrient deficit?… If there is a nutrient deficit, one of the signs of stress can be that the leaves start to curl, droop, turn yellow, and potentially drop off.
IIn my experience, potted citrus trees tend to be more susceptible to nutrient deficiencies, especially if they have been in the same pot for years, as the roots exhaust the available nutrients.
From my research I discovered, Magnesium and potassium deficiencies in the soil are likely to be the specific cause of leaves curling with leaves curling inwards more indicating magnesium and leaves curling downwards indicating potassium deficiency in the soil.
Leaves can also droop and turn yellow due to a lack of nutrients which may look like a curling leaf.
You can of course request a soil test where you send a sample of your soil off to a lab to determine the health of your soil.
Or you can use a citrus fertilizer to address the nutrient deficit, which is what I recommend.
Use a specialized citrus fertilizer (available at a garden center or on Amazon) rather than a multi-purpose fertilizer as a citrus feed contains all the nutrients that your lemon tree requires at the right concentrations to avoid over-fertilizing which can also cause your leaves to curl downwards.
With consistent monthly applications of fertilizer through the Spring and Summer the lemon leaves should begin to look a lot healthier rather than a curled appearance (always follow the manufacturer’s instructions).
I would not recommend applying any fertilizer in Fall or Winter as this is when your citrus trees are dormant and excess fertilizer can stimulate new growth which dies during winter.
Aphids and Spider Mites Can Cause Lemon Tree Leaves to Curl
From my research, I learned that there are a few insect pests that can attack your lemon tree and cause the leaves to curl.
Spider mites…
If you notice small yellow spots as well as curling leaves, then this indicates a spider mite infestation.
Spider mites are more common indoors because they prefer the dryer environment of houses, so often affect lemon trees that have been brought indoors for Winter protection.
How do you deal with spider mites? Misting the leaves regularly is very effective at displacing the spider mites as they dislike humidity and moisture. Washing the leaves with soapy dish water is something that I personally do and it is also a very effective treatment.
I advise trimming back any severely affected foliage, and the tree should recover.
Aphids…
Aphids can also be a problem as they seek to feed off the sap of your lemon tree which has the effect of curling the leaves.
Aphid attacks are not uncommon on lemon trees, and they usually attack the more tender younger leaves, but any serious damage is usually mitigated by a good garden ecology, and in my experience, any problem is not severe.
There are lots of insect predators (such as ladybugs) that prey on aphids as well as birds.
For a serious infestation of aphids, my solution is to use an insecticide such as neem oil, which is applied to the leaves of the lemon tree and kills the aphids.
Lemon trees usually recover very well from insect infestations if they are treated. Cut back any leaves that are severely affected, and any curling leaves should survive.
Do you have any more questions about lemon trees or any experiences you’d like to share? Please leave a comment below! I’d love to hear from you!!
Key Takeaways:
- Curling leaves on your lemon tree indicates drought stress due to underwatering, excess wind, and low humidity, which causes the leaves to curl to conserve moisture. Aphids feed on the sap of young emerging leaves, which causes them to curl up.
- Lemon tree leaves can curl when moved indoors due to nutrient-deficient soil, overwatering, and transplant shock.
- Lemon trees require full sun, regular fertilizer, and watering when the top two inches of the soil are dry. Spraying leaves can help increase humidity, which revives leaves and mitigates damage from pests.
- Use neem oil or an insecticide to treat insect infestations that can cause the leaves of lemon trees to curl.