If you notice your avocado tree leaves turning brown and you’re not sure what to do, you’ve come to the right place! There are many things that could lead to avocado tree leaves turning brown. We’ll look at the two most common causes and some other less common issues that may be causing leaf browning on your avocado tree.
Before we get started, how do you know if avocado tree leaves turning brown is a problem that needs to be addressed? A few avocado tree leaves turning brown and falling off usually isn’t a problem. It’s a normal part of the life cycle of a healthy tree to shed some leaves, just like we shed hair off our heads.
If it’s more than a few, there could be an issue that requires some steps to remedy. If that’s the case for your tree, keep reading to see why your avocado leaves could be turning brown and how to fix it.
Most Common Causes for Avocado Tree Leaves Turning Brown
Not Enough Water
Avocado trees need more water than many other fruit trees. If your avocado tree leaves are turning brown, it could be because the tree isn’t getting enough water.
This is especially likely to happen in hot weather. Trees release water to cool themselves through a process called transpiration. It’s similar to how our bodies use sweat to cool us down. Without enough water, the avocado tree won’t be able to cool itself and this can result in your avocado tree leaves turning brown.
How to Identify it:
In addition to the avocado tree leaves turning brown, the leaves will look and feel very dry. They may curl around the edges and even fall off.
How to fix it:
Check the moisture in the soil around your avocado tree by sticking your finger into it. Water the tree only when the top two to four inches are dry (overwatering can also cause problems so you don’t want to go too far the other way).
Water deeply so the moisture can sink down to about two feet below the surface of the soil. In hot weather check on the tree more often to ensure it doesn’t get too dry. The soil should be saturated enough that it holds together and feels like a wet sponge when you squeeze it.
Adding a layer of compost or mulch on top is helpful for keeping water in. With a two to four-inch layer of mulch or compost, the soil around your avocado tree stays moist longer and you’ll need to water it less often. As an added benefit, compost and mulch both add nutrients to the soil nourishing your avocado tree over time.
Chloride Salt Build-up in the Soil
Another common cause of avocado tree leaves turning brown is chloride build-up in the soil. sodium chloride is a salt that is naturally present in water- even fresh water and purified water. When water evaporates, chloride salt is left behind in the soil.
If the avocado tree receives a lot of shallow watering rather than deep watering, it can cause sodium chloride to build up in the soil. In very hot conditions, water evaporates faster which can also lead to more chloride build-up.
Avocado trees are more sensitive to chloride than many other plants. The roots absorb chloride and it accumulates within the tree over time. When the chloride level gets too high, it causes the leaves of your avocado tree to turn brown and eventually die.
How to Identify it:
Avocado tree leaves that turn brown due to chloride build-up start with the tips of the leaves turning brown. If not treated, the brown will continue to spread over the rest of the leaves eventually killing the leaves completely so that they fall off the tree.
If you’re not sure if you have a chloride build-up problem you can get a soil salinity test through your local extension office.
How to fix it:
Make sure your avocado tree has good drainage. If it does, you can use extra water to flush the excess salt from the soil. Water the avocado tree deeply at least twice a week for several weeks to help the chloride build-up leach out of the soil. This is the only way to remove chloride build-up once it has occurred.
If your avocado tree doesn’t have good drainage, you’ll need to address that problem first. Frequent, deep watering can cause root rot if the water is not able to drain properly.
Going forward, water your avocado tree regularly and deeply. This helps flush excess salt on a regular basis to keep chloride from building up in the soil.
Other Causes for Avocado Tree Leaves Turning Brown
Avocado tree leaves don’t often have issues with sun scorch on the leaves but there are some occasions where it can happen.
If you’ve recently planted a young avocado tree and you notice the avocado tree leaves turning brown, it could be sun scorch. A young tree that was in a shady nursery might have a bit of shock when planted in a sunny location, especially during summer. After a bit of time, the tree will get used to being in full sun. You may want to provide a bit of shade until the tree gets established.
Excessive heat (over 100 degrees) can also cause sun scorch, especially if there are multiple 100+ degree days in a row. Keeping your tree adequately watered helps prevent issues with sun scorch.
Very low Temperatures or Frost
If you notice your avocado tree leaves turning brown after a frost or string of very low temperatures, it could be a reaction to the cold. If this is the case, the tree will recover when the temperatures rise. Just leave it alone and it will take care of itself.
If your avocado leaves have brown spots on them rather than whole leaves or leaf tips turning brown, it could be a fungal disease such as scab, verticillium wilt, or alternaria.
The treatment of the disease depends on which disease your tree has. To learn more about recognizing and treating a diseased avocado tree read our article on 5 Common Avocado Tree Diseases.
A nutrient deficiency is another potential cause for avocado tree leaves turning brown. The most common deficiencies your avocado tree might have are zinc, nitrogen, or iron.
If your tree has a nutrient deficiency, the best course of action is to add fertilizer (there are many options including natural and organic) or organic matter like compost. Results from the soil test will tell you what kind of fertilizer is needed.
Pests can also cause problems with avocado tree leaves turning brown. Pests like lace bugs and grasshoppers feed on the leaves of avocado trees causing them to turn brown or have other problems. If your avocado tree leaves have holes in addition to brown spots, pests could be the issue. To learn more about identifying and treating pests, check out our post on 6 Common Avocado Tree Pests.
If the air is very humid, your avocado tree may be absorbing water faster than it can release it through transpiration. This causes edema, a build-up of water that damages the plant’s cells.
If your avocado tree has edema, you may see brown spots, a crumbly texture, or swollen veins on your avocado tree leaves.
To fix the problem, allow the soil to dry up before watering again.
The Most Important Thing to do for an Avocado Tree with Browning Leaves
After carefully tending an avocado tree the last thing you want to see is problems with your tree but unfortunately, avocado trees are prone to problems.
Avocado tree leaves turning brown can be scary if you don’t know what’s happening but it doesn’t mean all hope is lost. The good news is that most problems that cause avocado tree leaves to turn brown are treatable. With proper attention and care, your avocado tree will recover and continue to produce healthy fruit.
Check on your Trees Regularly
The most important thing you can do for your avocado tree is to check on it regularly. By keeping an eye on your trees, you’ll be able to identify problems quickly. If something doesn’t look right, try and figure out what’s going on before it becomes a major problem.
Identifying problems early means you’ll be able to treat any issues that crop up before they have a chance to cause too much damage or spread to other trees.
Wrapping up Avocado Tree Leaves Turning Brown
Avocado tree leaves turning brown is a frustrating problem but thankfully one that usually has a workable solution. Diagnosing the problem is often the hardest part. Once you know why your avocado tree leaves are turning brown you’ll be able to work towards fixing the problem so you can get back to enjoying those fresh, tasty, healthy avocados.
If you have more avocado questions, make sure to visit our Avocado Trees page. We have all kinds of useful information for you there including avocado tree care, specific information and growing tips for many different avocado varieties, tips on using avocados like how to freeze avocados and how to ripen avocados, and even whether or not dogs and cats can eat avocados!