We have a large lime tree, and while it was doing well at one point, it started to fall over onto our fence. So, after some heavy pruning, it started standing on its own again. However, almost every single leaf turned yellow and fell off. Not sure what to do, we took to the web in search of answers. While we had to dig around for information, we were able to find what was happening to our lime tree and what we could do about it. Here’s what we found.
If you find that your lime tree’s leaves are turning yellow, the tree is likely lacking in nutrients. A deficiency in nitrogen, zinc, iron, or manganese can cause your lime leaves to turn yellow and fall off. Other factors, such as overwatering or pests, can also be the root of the problem.
While this is a quick summary, we put together a guide to explore this further. In this article, we’ll be going in-depth into what could be causing your lime leaves to turn yellow, how you can fix this issue, as well as other factors you need to know to properly care for your lime tree. If you’re interested in learning more about these topics, let’s jump in.
Why Lime Tree Leaves Turn Yellow
As mentioned earlier, a reason why lime tree leaves turn yellow could from a nutritional deficiency. Like us, lime trees have nutritional needs and require sufficient levels of nutrients such as nitrogen, phosphorus, zinc, iron, and manganese to remain healthy and strong.
When you see your lime tree’s leaves yellowing, it may be going through something called chlorosis, which is a common occurrence when plants are suffering from a lack of iron. There’s also a chance your tree may also be experiencing a lack of other elements such as manganese and zinc.
This is why it’s usually a good idea to apply a good citrus fertilizer during growing seasons. This is usually at the start of spring or early summer.
In the off-seasons, when your lime tree is more dormant, it doesn’t require as many nutrients. So, giving it a break during these times can be helpful.
Which Fertilizer to Use
The best fertilizer to use for your lime tree is one that has a good NPK ratio. Nitrogen (N), phosphorus (P), and potassium (K) are the main nutrients in fertilizer, and lime trees benefit from a 2:1:1 ratio. Most fertilizers also contain zinc, iron, and manganese, which help balance the nutrition.
By getting a good fertilizer, you’re ensuring that your lime tree is receiving all of its essential nutrients. The fertilizers above will give you the proper NPK ratio while having small amounts of other supplemental nutrients.
Another factor to keep in mind is pH. Like other citrus trees, lime trees prefer soil with more acidity. Because of this, sandy loam soil can work well.
If you’re not sure about the pH of your soil, you can try experimenting with acidic fertilizers (coffee grounds are a natural and cheap way to do this), or you can get your soil tested for conclusive results.
How to Fertilize Planted Lime Trees
While both in-ground and container lime trees will benefit from fertilizers, they should be handled differently when using this formula.
For your lime trees planted in the ground, apply the appropriate amount of fertilizer as directed by the package instructions, and then follow by applying 1-3” of soil over the formula. Once you’ve done this, you can apply a good amount of water on top to help drip the fertilizer further into the soil and feed your tree.
Another way to give your lime tree the nutritional value it needs is with coffee grounds. Applying your leftover coffee grounds on your tree’s soil has great nutritional benefits as coffee has high amounts of nitrogen and is acidic, which helps balance the pH of the soil. You can use coffee grounds on both your in-ground and container lime trees.
How to Fertilize Potted Lime Trees
If you have your lime tree in a container, you’ll want to apply your fertilizer a little differently to help fix the yellow leaves.
A good rule of thumb is to apply two tablespoons of fertilizer for every gallon of soil.
The best time to do this is while you’re planting your tree, so mixing the fertilizer into the soil well will help get the best results.
Most other factors with the fertilizer will remain the same with planted trees, such as the NPK and the quality of the fertilizer. However, some fertilizers can overpower potted trees, so if you want a safer fertilizer, I recommend using mulch such as straw or compost. These materials will slowly break down and provide extra nutrients (as well as retain water in the soil).
Lastly, begin watering your container to start successfully feeding your lime tree.
Another issue that may be causing your lime tree leaves to turn yellow and fall off is overwatering. Overwatering your plants can also cause chlorosis, which we covered earlier.
When overwatering, you’re letting nutrients escape from the soil, which will cause things such as chlorosis to occur. Overwatering can also cause your tree’s leaves to fall off altogether, so it’s important to be mindful of how much you’re watering your lime tree.
How to Water Planted Lime Trees
As for your trees that are planted in-ground, if you think overwatering is your problem, be sure to wait until four to six inches of soil feels dry before watering again.
This is a good estimate to ensure you won’t be giving your lime tree too much water, and end up harming them in the long run. If you’re wondering how often you should water your lime tree, it’s ideal to water them once a week (twice if you live in a hot climate and you notice the soil dries fast).
If you notice that your lime tree leaves are yellow and dropping, and perk up after watering, you’ll likely want to increase your watering schedule. It’s better to give your lime tree a deep watering once or twice a week compared to a shallow watering daily.
How to Water Lime Trees in Containers
If your lime tree is planted in a container, wait until about two to four inches of the soil is dry to water again.
Similar to lime trees planted in the ground, you should give your tree a deep watering once or twice a week. You want to make sure to soak the soil for the best results, but keep an eye on it to make sure the soil drains properly and does not hold the water for more than a few days.
Following these tips will help keep your lime tree, as well as its leaves, green and healthy.
How to Repot a Lime Tree
If you find that your potted lime tree has yellow leaves due to collapsed soil or poor drainage, repotting it will likely be the best option. Additionally, you may want to repot your lime tree every 3-5 years, or when it outgrows its container.
To repot your lime tree, remove as much soil as possible (without damaging the roots), grab your tree from the base, and relocate it to its new pot. Water well, and apply any extra soil that condenses from the watering. You may want to mix some compost or fertilizer into the new soil beforehand.
Repotting is also a great way to keep your lime tree happy and healthy without having to constantly trim its roots.
To start repotting your lime tree, start by grabbing the tree by the base and slowly shifting the tree out of the soil. If needed, you can rock it back and forth to loosen up the soil.
After this, begin scooping an appropriate amount of soil into the new pot, so your tree is sitting at just the right height. You’ll want the start of the lime tree’s trunk to sit an inch or two below the top of the container. When transplanting, make sure to water the tree well to reduce the effects of transplant shock.
In the video below, you can watch step by step how The Elsinore Gardener successfully repotted his lime tree.
Root rot can occur on your lime tree when a fungus known as Phytophthora inhabits your lime tree’s soil. It can be caused by overwatering, excessive rainfall, or when bacteria travel from elsewhere through splashed dirt. However, most of the time root rot is caused by overwatering and poor soil drainage.
As a side-effect, root rot can cause your lime tree’s leaves to turn yellow and fall off, so it’s important to act fast when you see these signs show up on your lime tree. You can treat root rot by repotting your lime tree and adjusting your watering amount and schedule appropriately.
Alternaria is a fungal disease that can affect your lime trees’ young leaves. This disease can cause brown and yellow spots on your lime tree, so it’s important to keep an eye out for these signs.
To avoid Alternaria, make sure your trees have the appropriate spacing they need to thrive and grow. Giving your lime tree the space it needs from the start is key to avoiding diseases like Alternaria from forming later on.
If your lime tree’s leaves are yellowing or dropping, there’s a chance it might have whiteflies.
Whiteflies are small white bugs that look like flies (hence the name) and are closely related to aphids. They can be found in clusters underneath leaves and are typically found in warmer climates. Whiteflies feed on leaves which results in a sticky honeydew, which can introduce fungus to your lime tree.
If the whitefly population gets too large, they can feed on too many leaves, which results in a weak lime tree unable to properly photosynthesize. When this happens, the leaves turn yellow and fall off.
Most times, simply hosing your lime tree leaves with good pressured water can knock them off (I’ve done this with aphids and it worked well).
Other times, hosing whiteflies with water won’t work. In these cases, spraying soapy water will remove them and bind their wings and movement, which quickly prevents them from feeding. From there, they’ll soon die off.
Aphids are a common occurrence in most gardens and you’ll likely have to deal with them at one point or another. Like whiteflies, they suck nutrients from plants and can weaken the plant, causing leaves to yellow and drop.
They can range in a variety of colors, but the best way to identify them is to check under leaves. They can sometimes be too small to see, but their clusters can be fairly obvious. If you see wilting, yellowing, or damage to your lime tree’s leaves, try checking underneath them for clusters of white, black, or yellow dots.
Just like whiteflies, aphids can commonly be controlled by using a jet of water or a soapy spray.
I’ve had aphids on my kaffir lime tree before, and by using a hose (without a spray attachment) and covering the opening with my thumb, it was enough to create pressure to knock them off. They haven’t come back since.
For our lime tree, we found we needed to give it some time to heal from its pruning and provide a high-nitrogen fertilizer. However, your lime tree might be different, so be sure to check and use the process of elimination to rule out some common issues.
While we discussed the main reasons why your lime tree may be experiencing yellow leaves, generally, yellow leaves that are falling off are usually a sign that your tree is receiving too little or too much of something.
Factors such as too much bacteria, water, or even sunlight can cause yellow leaves. At the same time, a lack of essential nutrients or healthy bacteria can also cause your lime leaves to turn yellow.
Remember to start by investigating one part of the lime tree, such as the soil for any issues like collapsing or poor drainage. If you start with one part of the tree and use the process of elimination, you can usually find what’s wrong with your lime tree fairly quickly.