You could have a few avocado seedlings growing and thriving well, although you may have spotted the ends of their leaves of your avocado tree leaves turning brown. It can appear to be “tip burn,” a typical problem with avocado plants. But, most often, the reasons for avocado trees having brown leaves are.
Under-watering is a common cause of brown leaves on avocado trees. Other reasons are sunburn, frost, or water containing too many possible salts or chlorine. Getting rid of chlorine sounds complicated but is much easier than you think.
So, while under-watering is a typical cause of brown leaves on avocado trees, what are some additional causes, and what can be done about it?
In our guide, you can find the answers to why are my avocado leaves turning brown? By the end, you’ll see how to fix the issues and prevent avocado leaves browning quickly.(Learn How To Grow An Avocado Tree That Bears Fruit)
How To Water Avocado Trees
Because the roots don’t have enough moisture to supply and cool the leaf edges, under-watering avocado trees might make avocado leaves turn brown.
The avocado roots can stay cool and hydrated while simultaneously cooling and hydrating the rest of the plant if there is enough moisture in the first 4 inches of soil. Water can’t reach the trees canopy if the top 2-4 inches of soil on your avocado plant are bone-dry.
If this is the case, deep watering is the best method when leaves are turning brown.
Give your avocado plants 4 inches of water, water deeply every 2-4 weeks, so you moisten the top 4 inches of soil. If the soil is damp for over 24 hours, root rot might start.
If you live in a hot, dry area, you may need deep watering of your plants more frequently to stop brown tips on the leaf edges from spreading. If your soil is drying out too rapidly, try mulching it with leaves, bark, or pine needles to help keep moisture in the potting soil.
Deep watering is preferable to shallow watering because most plants benefit from it. After all, deep watering imitates rainfall.
Avocado trees are tropical, so they’re adapted to prolonged, heavy rainfall rather than short, shallow ones.
Shallow watering your avocado tree can cause several unforeseen consequences:
- It encourages shallow roots.
- Drought-resistant shallow roots can’t anchoring your tree.
- Shallow watering can’t flush salt, and excess salt accumulates.
When watering, be sure to water to the drip line of the leaves and not merely the tree’s base; this way, you cover the entire root zone, thus helping to stop avocado plant leaves browning .
Preventing Sunburn In Avocados
Avocado trees can also get sunburned from too much direct sunlight, resulting in browning leaf tips or all the leaf surface growing as they grow drier.
While determining whether the sun is causing browning leaves is tough, start by checking the tree’s watering, then the sun, frost, and finally the salt and chlorine in the water as brown leaf tips can be symptoms of many things.
If the tree leaves still turns brown despite providing enough water to keep the soil moist, make sure it isn’t blasted by the sun. (Read Where To Plant Avocado Tree)
Avocados, like other tropical fruiting trees, thrive in full light. The sun though, can be harsh in tropical areas; thus, your leaves turn brown as the leaf dries (desiccation)
As a result, it’s a good idea to monitor your avocado tree throughout the warmest part of the day. Overheating or dryness should be checked on the leaves and the top 2-4 inches of soil.
If you think the sun is getting too hot for your avocado tree and it’s drying out the leaves (and turning them brown), make the following changes:
- Mulch at the base of the avocado trees to keep the soil water and prevent the roots from drying up in the sun. 1-2 inches of leaves, bark, or pine needles might be used. To prevent mold or disease from spreading to the avocado tree, make the mulch at least 3 inches away from the stem or trunk.
- Allow the avocado tree to get sunshine from the north. While southern exposure provides more light, it can also be excessively hot for the plant at times.
- Also, because the afternoon is the warmest portion of the day, offer the tree some midday shade. You can use a vast umbrella or strategically position it among larger trees to provide shade in the afternoon to protect new leaves; it could be too late for damaged leaves as once they have turned brown, they are all but dead.
Stop Frost Harming Avocado Trees
Avocado leaves can also be killed by frost and become brown. The critical way to identify if frost is causing damage to your avocado tree, compared to the other causes, is if the leaves are browning and curling. Keep your avocado trees out of temperatures below 25 degrees Fahrenheit.
While avocado trees may withstand a brief cold, if you receive a longer or harder frost, cover outside avocado trees with sheets or bring any potted avocado trees inside until the frost passes. Avocado trees can be grown in a greenhouse in hardiness zones eight and below.
Reduce Salt Build-Up
Because potted avocado plants have a restricted quantity of soil to work with, salt and chlorine build-up are more likely. Small amounts of salt and chlorine can soon become potent as a result. Therefore, Hass avocados are more affected than Reed or other trees.
Salt accumulation in the soil can cause avocado tree leaves to dry and brown, eventually leading to leaf drop. Deep watering, vinegar, reverse osmosis, or chemical additions can all be used to remove salt from the soil and p[recent salt burn on leaves.
The issue here is that when we water our plants, the salts in the water (and fertilizer) build up in the soil, and you get leaf burn.
Salt is left behind after water evaporates from the soil and leaves. The excess salt then dries out the avocado leaves, turning them brown, beginning at the tips.
While many plants aren’t affected by too much salt, avocado trees are vulnerable to leaf burn from excess salt. Fortunately, there are a few methods for removing or reducing the salt content of the water you use to irrigate.
How to Reduce Soil Salt
- A deep watering
- Reverse osmosis (RO) is a process that purifies water
- Chemical additions
Deep watering is the most straightforward and practical approach to reducing or pushing salts from the soil and stopping leaf burn.
You’re using the excess water from deep watering your avocado tree to dissolve the salt and disseminate it farther into the soil to around 3-4 feet.
Vinegar, reverse osmosis, and chemical additives are more options for flushing salt from the soil.
While deep watering and vinegar are very simple to implement, reverse osmosis and chemical additions can be used to stop the leaves turning brown from leaf burn.
Chemical additives can assist remove salts to stop your avocado leaf burn.
- Calcium chloride is a mineral composed of calcium and chlorine
- Sulfuric acid (H2SO4)
- Iron Sulfate
- Aluminum Sulfate of aluminum
- Lime and sulfur
If you believe you have leaf burn from a salt build-up in your soil, you can send samples to a testing lab or purchase a home testing kit that covers salt build-up.
While testing, you can find an iron deficiency from alkaline soils can lead to your leaves browning.
High Chlorine Content Causing Brown Tipped Leaves
Because chlorine is commonly used to clean tap water, it’s not surprising that it can contain high levels of water.
Chlorine, like salt, can build up in the leaves and soil of avocado leaves, causing them to burn and brown. Use a charcoal filter or let the chlorine evaporate to eliminate chlorine from tap water.
There is less chlorine in some types of water than in others. Here are some instances of chlorinated water with high and low levels of chlorine.
High Chlorine Water
- Tap water
- Irrigation water
- Most treated waters
Low Chlorine Water
- Charcoal filtered water
- Chlorine evaporated water
- Distilled water
How to Reduce Chlorine in Water
To remove chlorine from tap water, there are two fairly easy methods.
- Filters made of charcoal
Allowing chlorine to evaporate is one of the simplest ways to eliminate chlorine from tap water. In most cases, this entails putting the water out in the open for 4 to 5 days. Then, let the water sit, and chlorine breaks down and evaporates.
You can also use a charcoal filter to eliminate chlorine, and you’ll find many types of water filters featuring charcoal filters from home drinking water or for use in aquariums.
However, keep in mind that while these two procedures remove chlorine, they do not eliminate chloramines. As a result, there’s still a potential that your avocado tree will become chemically burned and develop brown leaves.
While chlorine evaporation and charcoal filters are a great initial step for leaves turning brown, consider adding a second phase of reverse osmosis to eliminate all chloramines.
Because reverse osmosis systems are costly, test if your avocado tree does better with chlorine-evaporated or charcoal-filtered water first, if these approaches are ineffective, consider using reverse osmosis. (Learn Why Does My Spider Plant Have Brown Tips)
To remove both salt and chlorine leave the water to sit for 4.5 days (removing the chlorine) before adding 4 inches of water.
This should be done every 2-4 weeks or whenever the top 2-4 inches of soil are entirely dry. Avocado tree watering concerns, such as yellow or drooping leaves, can be avoided by correcting the watering.
It’s important to remember that up to 10% of the leaves may be brown. Unless the proportion is higher, you shouldn’t need to do anything as there will be new growth to replace it.
Finally, there’s no need to remove the plant’s brown-tipped old leaves. The green on the leaves is still functional, and the leaves will shed on their own if necessary. This produces an excellent mulch and can help other plants in the garden, especially if your little avocado trees have partner plants!