Contrary to popular belief, leaf curling on lemon trees is not always caused by pests or disease. In some cases, too much or too little water can cause the leaves of your lemon tree to curl. This is a common problem caused by improper watering or too much direct sunlight. Understanding why your lemon tree’s leaves are curling is an important step in correcting the issue.
The first indication of excess water is yellow and limp leaves. This occurs when there is a lack of drainage in the soil, so the roots of the lemon tree stay wet. If your plant is in an area that receives too much water or allowed to sit in a pot with standing water, the leaves will become discolored and curl. You should reduce waterings and make sure the soil is well-drained.
Conversely, if the leaves of your lemon tree are dry, discolored and curled, it is likely you are not providing sufficient irrigation. Overly dry soil, and in most cases, soil that does not hold moisture, can prevent the water from reaching the roots of the lemon tree. Wilting can also be caused directly by wind, extreme temperatures, excessive light, or drought. In this case, use a hose to water your lemon tree regularly and increase humidity levels by misting the leaves and soil. Additionally, you should move the lemon tree to a sheltered, partial-shade area to protect it from the elements.
In addition to water and moisture, it is important to consider the fertilizer that you are using. Be sure to always use fertilizer specifically formulated for lemons, as other fertilizers might not provide the right amount of nitrogen. Too much nitrogen can cause the leaves of the lemon tree to curl downwards, while too little will cause the leaves to curl upwards. In general, a ratio of 2 parts nitrogen to 2 parts phosphorus to 2 parts potassium is ideal for healthy lemon trees.
Finally, if none of the above causes solve your lemon tree’s leaf curling issue, it’s possible that the plant has contracted a virus or been infested by an insect. Check for signs of insect infestations, and if signs are found, take the necessary steps to treat the plant. Varroa mites, spider mites, mealybugs, and aphids can all cause leaf curling on lemon trees. If you believe a virus or insect infestation may be the cause of the issue, you’ll need to take the lemon tree to an arborist or horticulturist as soon as possible.
Inadequate Sunlight
Inadequate sunlight can also lead to leaf curling on lemon trees. Generally speaking, the optimal range for soils and containers for lemon trees is 6-7 hours of direct sunlight. Extreme heat or cold may damage the lemon tree. If your lemon tree is exposed to intensive sunlight, the leaves may turn yellow and curl up. Due to such extreme ultraviolet radiation, the chlorophyll present in the leaves were destroyed. In this case, move your lemon tree to dapple or layered light.
Low Humidity
Low humidity in the environment can cause lemon tree leaves to curl. With lower levels of moisture, the leaves may become dry and brittle, leading to fatigue and curl. Regular misting of the leaves at least once a day will help increase humidity and make the leaves smooth again. If humidity is not the issue, you may also add plastic sheeting to the environment to create a moist and humid microclimate.
Soil Nutrients
Often times, soil with inadequate nutrition will lead to lemon tree leaves curling. The soil should have a balanced mix of nitrogen, phosphorus, potassium and trace minerals like zinc, iron, and mag.. If you notice that the lemon tree leaves are curling and the soil lacks nutrition, you’ll need to amend the soil with a mineral-rich fertilizer. Pay special attention to the nitrogen content, as too much nitrogen can cause leaves to curl down, while insufficient nitrogen will cause leaves to curl up.
Pests
In some cases, pests like varroa mites, spider mites, mealybugs, and aphids can cause lemon leaves to curl. These pests can attack the plant and cause it to curl the leaves to protect itself. If you spot any of these pests on your lemon tree, you should treat the plant with an appropriate insecticide as soon as possible. Additionally, it’s important to remove the affected leaves after treatment, and make sure to follow up with a full inspection of the tree.
