Your beautiful lemon trees should produce yellow fruit, not yellow leaves. If you can see your tree’s green leaves are becoming yellow, whether, in spots or all over, this can be concerning. You might wonder if your tree is sick and what you can do, especially because yellowing foliage could result in a poor lemon harvest.
Lemon tree leaves usually turn yellow if the tree is overwatered or it lacks the essential nutrients it needs to grow healthy foliage and fruit. There are other reasons why your lemon tree leaves can become yellow, such as if the tree is exposed to extreme temperature fluctuations.
In this article, we’ll explore everything you need to know about why your lemon tree leaves are turning yellow and how to fix the problem.
Why Are Lemon Tree Leaves Turning Yellow?
Lemon tree leaves can start to turn yellow for a variety of reasons. These include the following.
- Overwatering. Although your lemon trees want to be watered regularly, especially if the weather is hot, you don’t want to water them too much. Overwatering causes the nutrients in the soil to get leached, and this also saturates the roots, causing root rot. Once the roots are damaged, they won’t be able to draw nutrients from the soil to nourish the plant. Root rot can be fatal to plants, so you don’t want to overwater your tree.
- Dehydration. On the other hand, if your lemon tree isn’t watered enough, this can cause it to become dehydrated, of which yellow leaves are a common symptom. This is especially important to remember if you live in a very dry region.
- Lack of nutrients. You should fertilize your lemon tree regularly to prevent yellow leaves that arise from nutrient deficiency. Nitrogen, for example, is an essential nutrient. If your lemon tree doesn’t get enough nitrogen, the tree will take nitrogen from older leaves on the tree and direct it to new foliage growth. So, if you can see older leaves on the tree are turning yellow, this indicates a lack of nitrogen. You want to give your citrus tree fertilizer during spring and summer when it’s experiencing growth.
- Low temperatures. If your lemon tree is exposed to temperatures that are lower than 50°F (10°C), you might notice its leaves will start to turn yellow. Maintain a healthy temperature range that’s between 50-80°F (10-26.6°C).
- Sudden fluctuations in temperature. If your lemon tree is growing indoors and it’s being exposed to sudden temperature changes, this can also affect it and cause its leaves to become yellow.
- Pest infestations. Some common pests, such as aphids, can attack lemon trees and suck nutrients from their leaves. This can cause them to become damaged and turn yellow. Make sure you treat pest infestations with horticultural oil, which you can make yourself. Mix together two tablespoons of baking soda, two tablespoons of olive oil soap, and five tablespoons of hydrogen peroxide, and mix them into one gallon (3.7l) of water.
How to Prevent Yellowing Leaves in Lemon Tree
Although you can treat yellowing leaves in a lemon tree, prevention is better than cure. You can prevent your lemon tree from getting yellow leaves by following some important tips and following the correct regimen of care. These include the following:
- Give your lemon tree at least six hours of sunlight every day. If your lemon tree is indoors in a pot, make sure you place it in a window that gets a lot of sunshine.
- Water your young lemon trees and established ones with about two inches (5.08cm) of water every week. But, if the temperature in your region gets hotter than about 80°F (26.6°C), you will have to water your tree more regularly so that it doesn’t dry out.
- Plant your lemon tree in well-draining soil. This will prevent water from causing root rot. If you’re growing your lemon tree in a container or pot, you must give it a light potting mix so that its soil won’t become too compacted. This makes it difficult for your lemon tree’s roots to access water and nutrients from it.
- Bring your potted lemon trees indoors during the winter. This will ensure that they aren’t exposed to cold temperatures that can damage their foliage.
- Feed your lemon tree with a complete NPK fertilizer containing a blend of nitrogen, phosphorus, and potassium. This will keep your tree growing healthy and ensure it produces lemons. You should fertilize your lemon tree in spring and every month in the summer.
- Prune your trees. This will ensure that your trees can direct energy into producing healthy leaves and fruit. You should prune long branches that also make the tree become unruly. Pinch the leaves to encourage the flowers to grow.
What About Yellow Spots on Lemon Tree Leaves?
If your lemon tree leaves are getting yellow spots on them instead of turning completely yellow, this could be caused by diseases, pests, and other reasons. Here are the main causes of yellow spots on leaves and what you can do to eliminate them.
Citrus Greening Disease
This plant disease is caused by the Candidatus Liberibacter species of bacteria. If your lemon tree has a citrus greening disease, it will also have other symptoms, such as stunted tree growth and lemons that fall off the tree prematurely.
An insect known as Asian Citrus Psyllid (ACP) transmits the disease by eating the leaves of the citrus tree. Citrus greening disease presents with symptoms such as mottled leaves. Sadly, once this disease takes hold, there is no cure for it.
To prevent it, you have to prevent the spread of the ACP insect. You can do this by following quarantine state rules pertaining to purchasing and transporting citrus trees and ensuring you only purchase your trees from reputable garden centers so that the plants aren’t infected.
Lack of Nutrients
Nutrient deficiencies can cause yellow spots on your citrus tree’s leaves. So, make sure you feed your tree an NPK fertilizer. As we mentioned earlier, this will also prevent the general yellowing of leaves.
However, if your tree’s leaves have blotchy yellow spots on them around the midribs, this is usually a symptom of a lack of micronutrients like iron or manganese. You can supplement this with a citrus fertilizer that provides these micronutrients.
Note that if your lemon tree isn’t getting enough magnesium from the soil, this could be because the soil pH is lower than 5.0. By increasing it with the additional component of lime, the pH will reach between 6.0 and 8.0. With the right soil pH, the lemon tree will be able to draw magnesium from the soil much easier.
Lack of Proper Care
If your lemon tree isn’t planted in an area of the garden where it gets enough sunlight, water, and well-draining soil, it will suffer from a lack of care and produce yellow, blotchy leaves. Make sure you:
- Keep your lemon tree away from sites where it’s exposed to sudden, drastic temperature changes. Outside, your lemon tree should be shielded from strong winds. Indoors, lemon trees need to be kept away from drafts.
- Very hot or cold temperatures. Maintain a healthy temperature that doesn’t dip lower than 50°F (10°C).
- Too much sunlight. Check your lemon tree for signs that it’s getting too much sun, such as brown spots, rotting fruit, or stunted growth.
- Give your lemon tree enough soil drainage. Signs that your lemon tree isn’t planted in well-draining soil include curling, yellowing, or wilting leaves.
- Mulch your lemon tree. This serves to ensure its soil maintains the correct moisture. Spread the mulch in a two-foot (0.6m) diameter around the citrus tree.
Spider mites, a common gardening pest, can attack your lemon tree leaves and cause yellow spots on them because they suck sap from the leaves. You might also see webbing around the leaves, which indicates that spider mites are present.
Other pests that can cause yellow spots on leaves include scale insects and stink bugs. You can eliminate them from your trees by applying insecticidal soaps or neem oil.
Planting a lemon tree is a great way to produce and enjoy your own lemons, but if you can see that your lemon tree’s leaves are turning yellow or getting yellow spots on them, you might wonder what to do.
This article outlines the important tips to follow to care for your lemon tree properly and ensure it grows healthy green leaves, such as:
- Planting your lemon trees in an area that gets at least six hours of sunlight every day.
- Planting your lemon tree in well-draining soil.
- Watering your lemon tree with about two inches (5.08cm) of water every week.