Whether you’ve spent weeks waiting for your avocado seed to sprout, or you just brought home a little plant from the nursery, it can be disheartening to see the leaves curling, becoming dry, and maybe even dropping off the plant.
Your first instinct might be to reach for the watering can – but wait! There are several reasons why your avocado plant’s leaves might be curling, and with a bit of know-how, you’ll be able to spot the cause and fix the problem easily.
Low humidity and underwatering are the most common causes of avocado leaves curling. Root rot is another potential cause of this issue. With too much water, the roots get damaged and the plant eventually drowns. The leaves get no water from the damaged roots, curl up then drop off.
In this article, I’ll take you through this and the other causes of leaf curl in avocado plants. You’re sure to find the answer to your plant’s problem!
Causes of Avocado Leaves Curling
Probably the simplest explanation for curling leaves on your avocado plant is lack of water. If the leaves are curling downwards, drooping, or looking crispy, this could be the reason.
Avocados are subtropical plants and like a humid environment with plenty of water, and it is important to keep their soil well-draining, consistently moist but not wet.
If they don’t get enough water the cells in their leaves begin to collapse, causing the curling effect.
However, under watering is not the most common reason for curling leaves on avocado plants, so hold off before you douse your plant!
- Make sure your avocado plant is living in a rich, well-draining potting medium.
- Check your plant every day: pick the pot up, if it feels light your plant probably needs a drink. Ditto if the top couple of inches of the soil are dry (use your finger to check!).
- Water deeply and consistently at the root, every few days rather than a little bit each day.
- Although the avocado plant loves moisture, with potted avocado plants it’s better to err on the side of under watering than overwatering.
Overfeeding with Fertilizer
To thrive, avocado plants need a mix of nitrogen, potassium, magnesium, and phosphorus as well as trace amounts of other minerals.
Feeding your avocado plant regularly will ensure it gets the nutrients it needs, but make sure you don’t give your plant too much food!
Avocado plants that receive too much fertilizer will develop weak growth and limp, yellowing leaves, sometimes with brown tips.
The minerals in the fertilizer build up in the soil and cause root burn, which stops the plants’ roots from working properly and causes these issues.
It is important to properly dilute the plant food using the instructions on the packet, as using too much will lead to over-fertilization.
Avocado plants don’t need a special type of fertilizer and are happy with a general-purpose 20-20-20 houseplant food.
- Treat your avocado plant like any other houseplant and feed every couple of weeks or during the growing season.
- Use a general-purpose 20-20-20 plant fertilizer and follow the instructions.
- Stop feeding during winter when the plant’s growth slows down.
Lack of Nutrition
Nutrient deficiencies in plants can show themselves in many different ways, and curling leaves is one of them.
Potted plants are particularly prone to nutrient deficiencies as they only have access to a very limited amount of growing medium.
Over time, nutrients in the soil become depleted as the plant uses them, and processes that would naturally replenish nutrients don’t occur.
If you’ve had your plant for a while, watched it grow, and never fed it, chances are it will appreciate a feed!
Curling and yellowing leaves could be a sign of deficiency in potassium, magnesium, phosphorus, or nitrogen. (Source: University of Delaware)
- Feed your avocado plant every two weeks with 20-20-20 fertilizer.
- Repotting in spring with a fresh potting medium will give it a boost after the winter lull.
Avocado plants prefer an environmental temperature of 60– 85 °F (15-30°C) and will show signs of distress if kept in a colder or warmer situation.
In cold temperatures, the plant’s systems can’t function properly and the plant may go dormant or in very cold temperatures it could die.
In very hot temperatures the plant is unable to cope on a cellular level and the plant’s cells will begin to collapse in the heat.
If you’ve recently moved your avocado plant to a new location then noticed its leaves start to curl, it could be suffering from temperature stress.
Moving from indoors to outdoors or vice versa, or even a move to a different part of the house can cause temperature stress.
In extreme cases, this can cause the plant to drop all its leaves, and although the problem is not usually so severe it is important to take measures against temperature stress.
- Avoid moving your plant between areas with very different conditions.
- Drafts from windows and heat from radiators can have a big effect on the temperature of the air around the plant, so pay attention to where you put it!
- If you need to move your plant, help it to acclimatize to the new location by doing it over a few days – put the plant in its new location during the daytime then back at night.
Root Rot from Overwatering
Overwatering is a killer for houseplants, including avocados. It produces symptoms similar to those of under watering, often prompting another watering – worsening the issue.
If a plant’s roots are surrounded by water so that air can’t get to them, they suffocate and die.
These dead roots can then become infected with root rot which can spread to the healthy roots.
Eventually this will show in the leaves of the plant as the cells can’t receive enough moisture from the roots.
The problem will kill the plant unless treated.
- Don’t overwater your avocado plant. Let the soil dry out between watering’s and check the top of the compost – if it’s dry a couple of inches down you can water.
- Depending on where you live, watering once a week to every couple of days should be sufficient.
- If you notice signs of root rot or even suspect it, immediately re-pot the plant in fresh potting medium, removing any dead roots and as much of the previous compost as possible.
- Do not reuse growing medium infected with root rot without sterilizing it first.
Tap water contains substances that can build up in the compost of container plants, causing a variety of problems including curling leaves.
When these substances are in too high quantities they can burn plant roots and cause a lot of damage.
This is a particular problem in areas with hard water, which contains a higher proportion of minerals.
The minerals from the tap water build up in the soil of container plants, causing similar problems to those of over-fertilization.
Tap water contains chloride and fluoride. Which are meant to kill all kids of germs.
It can also kill the beneficial microbes within the soil. Microbes are essential to make the nutrients available for the plants.
If the roots are not getting nutrients it will show symptoms like curling leaves.
Avocado plants are very sensitive to salts so it is especially important to pay attention to the levels of mineral build-up in your soil. (Source: University of Florida)
- Make sure to re-pot your avocado plant in fresh medium at least once a year, ideally in spring.
- Give the roots a gentle shower to remove build-up before repotting.
- Watch out for crusty build-up on the top of the soil in your containers and re-pot immediately if you notice any!
- If you live in an area with very hard water, consider using a water filter before watering your plants.
Too Much Direct Sunlight
If your avocado plant is on a sunny windowsill and you’ve noticed the leaves beginning to curl, it’s probably getting too much sun and starting to burn!
Although avocados love the sun, the direct rays intensified by the glass of a window can be too much, especially for young plants.
The strong sunlight causes the plant to lose water from its leaves quickly, and to protect itself the plant curls up its leaves to lower the surface area exposed to the sun. You may also find brown spots due to excessive sun exposure.
- Keep your plant where it gets a lot of bright, indirect light – close to a south-facing window but out of the sun would be perfect.
- Young plants need more protection from the sun’s rays.
- Your avocado plant will be much happier outside during sunny weather and will be able to tolerate direct sunlight better, although it might need some shade during the hottest parts of the day.
I have written an article on causes and solutions of brown spots on avocado leaves, it will answer all the possibles questions you might have.
Lack of Light
Avocado plants need a lot of light to thrive. If you see your plant growing towards the window, or leaves in the darkest areas curling up and dying, you need to move your plant!
When growing in their natural environment, young avocado plants grow in partial shade from older trees and are usually happiest in indirect light.
As the plants mature, their cells become tougher and more able to tolerate strong, direct sunlight.
- If your plant is indoors, make sure it is getting plenty of bright, indirect light.
- LED grow lights installed indoors will ensure your plant gets all the light it needs.
- Consider moving the plant outside if possible, if only for a few hours a day.
Fungal infections are the main disease threat to container-bound avocado plants.
Root rot is a type of fungal disease that can first show itself in curling leaves that look as if they need water.
As the roots rot, they become unable to pass water up the plant causing dehydration symptoms.
Other types of fungal diseases such as powdery mildew can also affect avocado plants, with bad cases causing leaves to curl and die off.
Avocado trees can also be affected by cankers which cause ‘sores’ on the bark of the tree, and a disease called sunblotch which causes discolored, distorted growth.
- Don’t let your avocado plant become waterlogged as this encourages root rot.
- Don’t keep your plant too dry as this can lead to powdery mildew.
- Keep the surface of the potting medium free of debris such as fallen leaves.
- Inspect your plant every day for signs of disease.
- Use a fungicide to kill off the invading fungus, although without taking steps to improve the plant’s situation this won’t help much.
Avocado plants kept outside are more likely to fall prey to insect infestation than those kept indoors.
Avocados can fall prey to several plant predators including:
- Tree Borers.
- Lace bugs.
These insects cause damage to the plant either by attaching themselves to the leaves and sucking out the juices of the leaves. Insects like mites and scale munch through the leaves as a caterpillar does.
- A weak solution of dish soap and water sprayed onto the plant will deal with many of the insect invaders.
- You could also try rubbing alcohol to eliminate the soft skinned insects like thrips and aphids, though this is quite harsh and could damage the plant.
- Other ways of dealing with insect issues are special horticultural oils which are applied to the plant, pesticides, and predatory insects.
Perhaps the least obvious cause of leaf curl and one of the most common for housebound avocado plants!
A lack of moisture in the air essentially desiccates the plants – sucking the water out of them. The leaves start to curl before eventually turning brown and falling off.
Low humidity can kill plants very quickly so it is important to take action as soon as possible!
Avocado plants like a humidity level of around 70 – 80 percent, but can tolerate levels down to 45%.
- Increase the humidity in your home to at least 45%.
- Try making humidifier trays: place pebbles in trays of water, making sure the water doesn’t cover the pebbles. Put plant containers on top of the pebbles and the plant will enjoy the local humidity without getting waterlogged roots. Don’t forget to keep the trays topped up!
- Increase local humidity by having more plants in the room and keeping them close together.
Avocado Plant Leaves Curling After Repotting
Sometimes repotting a plant goes wrong. Maybe you dropped the plant or accidentally broke off some of its roots, or maybe you used the wrong potting medium.
If you find that the leaves of your avocado plant are curling after repotting, think about how you repotted it.
If the plant got a shock like losing some roots this will often show as dropping leaves.
The good news is that unless the shock was too bad, the plant will likely recover if treated carefully.
When your plant didn’t receive a shock during repotting, think about the pot and potting medium you’ve used.
If it is too heavy, wet, or compacted this could be causing your plant problems. When the pot is too big, this can encourage root rot.
- Be careful when repotting avocado plants! Although they are not the most fragile plants their roots are delicate and can be damaged easily.
- Make sure to use an appropriate potting medium
- Increase your plant’s pot size gradually – a couple of inches each time is plenty.
How To Prevent Avocado Leaves Curling?
- Make sure the plant is getting the right amount of water.
- Feed your plant during the growing season.
- Keep your plant in a place with a stable temperature of.
- Ensure your plant gets plenty of bright, indirect sunlight.
- Keep watch for invading insects and diseases.
- Increase the humidity of your home.
- Treat your plant gently when repotting.
- Use an appropriate potting medium and pot size.
Don’t resign yourself to curling leaves on your avocado plant! Use the solutions presented here to fix the problem for good. Check:
- Water levels.
- Nutrient levels.
- Light and temperature levels.
- Signs of pests and diseases.
Mention how the reader can make sure that. Please mention Frequency and amount of water or watering rules.
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