Lemons belong to the group of evergreen plants and, as the name implies, remain green the whole year. If it turns into a different color, something must be going in with your tree. The process known as chlorosis, lemon leaves yellow because of many factors—from a cultural mistake to a plant’s natural cycle.
Lemon tree leaves turning yellow could be easily interpreted as a lemon tree disease or a mistake that would make us question our worthiness and existence as green moms or dads. But don’t worry! This article covers the primary reasons why are my lemon tree leaves turning yellow to prevent lemon tree leaf problems in the future. We have also listed some immediate solutions as first-aid for your ailing tree.
Why Is My Lemon Tree Losing Leaves?
Usually, the leaves drop after showing yellowing symptoms, and early detection is the key to preventing your lemon tree dropping leaves. The following are some of the reasons why your lemon tree turns yellow or defoliate:
Lemon tree leaf discoloration indicates that there could be an abrupt change in temperatures in the past few days, especially if it was placed outdoors.
Solution: There is no solution to fix a tree that was exposed to fluctuating temperatures. Usually, the tree would typically spring up on its own in the next few days. However, you may put it indoors for potted trees if there is a forecast of temperature swings that usually occur in spring. To ensure that your tree gets the best care, subscribe to our exclusive PlantIn care plan.
If your plant is potted or you are entering the dry season, lemon tree losing leaves is often related to a cultural mistakes like watering. Potted trees lose water faster than soil-planted ones.
Solution: Like many plants, lemons like to be moderately watered. If it has not been watered for a long time, do not splash water immediately. Slowly irrigate water in low volumes and gradually increase it in the next couple of days. On the other hand, overwatered plants will not promote a new leaf growth unless the watering is properly done. If you want detailed tips and a correct watering schedule, please subscribe to our care plan.
An overwatered lemon tree will show curling of the leaves that would sometimes lead to defoliation.
Solution: Let the soil dry, and the plant will tend to adjust its water absorption rate. You can also rescue it by repotting if it has been sitting for a long time in wet soil. If it has already defoliated, the best thing to do is expose it outside to let the soil dry faster and follow the proper watering schedule.
General, patchy, mottled, or vein yellowing in the leaves is also a sign of nutritional deficiency.
Solution: You can easily treat your lemon tree by applying a complete fertilizer (NPK) if the yellowing is uniform in the leaves. They are heavy feeders or fertilizers. Mottled leaves or yellowing of the midribs is probably due to the lack of micronutrients such as Zinc, Iron, or Manganese. Know when to fertilize lemon trees by detailed instructions in our care plan.
If you have already applied fertilizers and no signs of new growth appear, then this is probably a sign of a fungal disease.
Solution: Strong systemic fungicides (with active ingredient thiophanate-methyl or benzimidazole) might stop the infection. However, this will not cure the plant. Sometimes, the plant can survive by containing the fungus by developing a complex, impenetrable layer of tissue in the roots or stem. Suppose you have multiple trees in your backyard. In that case, the best control is to cut the infected tree to avoid contracting the healthy ones.
Some viruses and bacteria also make the leaves yellow and deformed (curling, cupping, or malformed).
Solution: There has been no known treatment to treat a sick lemon tree infected with viruses and bacteria. We suggest just cutting it and avoiding the spread of the plant virus and bacteria. As the saying goes, an ounce of prevention is worth a pound of cure. It is best to prevent it by applying systemic insecticides if you spot many brown aphids that look like tiny dots under the leaves that can transmit the virus.
Yellow and curled foliage with some brown spots on citrus leaves signals that tiny pests may be feasting under the leaves, such as aphids, mites, or plant hoppers.
Solution: Apply plant-based pesticides such as pyrethrum or rosemary oil in the late afternoon. You can also easily control them by blasting the tree with strong pressurized water. In this manner, the tiny insects will easily be dislodged and killed.
This is usually one of the problems with lemon trees in pots if transferred and grown indoors. Citrus are sun-loving plants and should be placed under complete sunlight.
Solution: Place your plant in the brightest part of the house, such as on the balcony or east or west-facing window. The defoliated tree might spring up after exposure to light. When putting a potted plant indoors, please do not do it abruptly, but rather slowly exposing it to a shade (morning/afternoon sun in the first few weeks and then total the following week indoors)
Yellow leaves on citrus trees in pots or in the soil is a sign of plant stress that could be one of the above conditions
Solution: It is best to identify the problem first and stop exposing your lemon tree to what is causing it. Usually, this occurs in plants that are suddenly moved from one place to another with varying conditions (light, temperature, watering).
Why Are the Meyer Lemon Tree Leaves Turning Yellow?
Meyer lemon trees primarily turn yellow because of nitrogen or micronutrient deficiency. They have a pretty voracious appetite for fertilizer. Nitrogen is needed to produce chlorophyll, which is the green pigment of the plant. Other micronutrients might also play a role in yellowing, so it is best to fertilize your plant with a complete fertilizer along with the trace elements like Zinc, Iron, and Manganese.
A general yellowing occurs when the deficiency is due to nitrogen. In contrast, mottles or yellowing between the leaf veins happens when micronutrients are lacking.
Uneven yellowing of the leaves might also be related to insect-transmitted viruses and bacteria like citrus Huanglongbing disease of Citrus Tristeza virus (CTV). However, this only likely happens if it has been previously bugged by brown aphids or hoppers feeding on your leaves or shoots.
Other cultural factors also play an essential role in keeping your Meyer lemon trees healthy such as irrigation and environmental conditions. Like many trees, lemons prefer moderately moist soil. Proper watering should be done to prevent yellowing, especially in the hot season or if your Meyer lemon is potted. The water quickly evaporates as the pot is exposed to sunlight.
On the other hand, although the Meyer citrus tree can survive fluctuating temperature and intense sunlight, the leaves tend to yellow in response to these changes. However, they can quickly spring up when the conditions become favorable.
Other Problems With Lemon Trees in Pots
Other problems can occur in lemon trees in a pot. Early detection is usually the key to preventing this, as there is no cure for a leafless tree.
Sudden Leaves Dropping
This occurs if the tree is exposed to sudden temperature fluctuations, overwatering, or underwatering.
Solution: Slowly acclimate your plant when moving from one spot to another. Have your plant correctly watered to prevent this. It is crucial to detect a lemon tree disease in time to predict leaves dropping. Use our PlantIn app to guide you through the proper watering of your plant to avoid this problem.
Leaf Turning Brown
Leaves that turn brown prematurely could be a sign of sun-scorch. This is true for trees were sitting for too long indoors and were placed under full sunlight
Solution: Gradually expose your plant when moving outdoors or vice versa. Doing so would give the time for the tree to adjust to the sudden shift of conditions outdoors.
Tiny brown lesions on the leaves are caused by a number of fungal species.
Solution: Manually pick the leaves with brown spots if only a few of them are on the trees. Otherwise, you will need to apply a potent fungicide (copper hydroxide, chlorothalonil, and flusilazole). Pruning some branches early in spring will also reduce its occurrence.
Flower and Fruit Drop
Potted lemon trees often flower and abort the little fruits before they mature. The possible explanation is that it is too young or it doesn’t receive enough nutrients.
Solution: Focus more on the proper nutrition of your plant to prevent the flower fruit drop as young trees tend to shed the flowers naturally. Watering should also be followed accordingly to avoid premature falling of the fruit. For specific nutritional advice, subscribe to our PlantIn care plan.
If your lemon tree has no new growth or has lost its vigor, the soil must already be compact. The roots seek more space and could have the “swirling effect” below the pot, searching for fresh earth and bigger space.
Solution: Replace your pot with a bigger plant container, and ensure that it has a drainage hole to let excess water flow out. When transplanting, trim the bottom roots that are tangled and swirled below the pot.
How Can You Tell If a Lemon Tree Is Overwatered?
The leaves of an overwatered lemon tree will appear rolled up than their usual turgid appearance. At a later stage, the curled leaves can turn yellow or brown and suddenly drop. Flowers and little fruits will also abort or turn black if it is in the blooming stage.
How Can You Treat Yellow Leaves on a Lemon Tree?
Treat yellow leaves by fertilizing your lemon tree with an ample dose of nitrogen or micronutrients such as zinc, iron, and manganese, which are likely the most probable causes of discoloring the leaves. Other issues should also be addressed to prevent yellow leaves from recurring, such as inconsistent watering, poor sunlight, and the presence of pests.
Do Lemon Tree Leaves Turn Yellow in Winter?
Yellow patchy leaves in winter are a typical plant response due to temperature change, especially if your lemon tree is placed outdoors. While it can be tempting to help it spring up, the best care is to let it stay dormant in winter and only fertilize it in spring.