In the wild, Avocado trees grow up to six feet (2 meters) before branching out from the main stem. They also receive plenty of light.
Avocado trees can quickly become leggy when we grow them indoors – the single spindly stem reaching upwards, a crown of leaves, and no branches.
Thankfully it’s not too difficult to encourage an Avocado to branch out once you understand why it has become leggy. In this article, we’ll look at the causes of legginess and what you can do about it.
To fix a leggy Avocado tree:
- Give the plant enough light
- Trim your avocados’ central stem to half its height when it reaches 6-8 inches (15-20 cm.)
- Make sure it has the right kind of potting mix and the right size pot
- Keep the temperature stable around the plant
What Does Leggy Mean?
When we say a plant is ‘leggy’, we mean that its growth is tall but thin and without many leaves or flowers.
For annual plants that die off in winter, legginess is often a natural part of their end-of-life cycle.
However, for perennials and trees like Avocado, the main reason why plants become leggy is lack of light and inadequate pruning.
Causes of A Leggy Avocado Plant
The primary cause of the Avocado plant’s leggy growth is a lack of light. Pruning on a regular basis is an effective way to promote growth in the lower portions of the stem.
Pruning may shorten the duration of new growth, but it will help the stem become stronger and rid it of legginess.
Lack of Light
When they don’t get enough light, Avocado plants quickly grow tall and spindly. Plants need light to perform photosynthesis – the process by which they produce food.
During photosynthesis, light reacts with the green chlorophyll in a plant’s leaves, along with carbon dioxide and water. The result is oxygen and glucose, which the plant then uses for growth or stores to use later.
Without an adequate light source, Avocados can’t produce enough food. They go into ’emergency mode’ and use their remaining energy to put on a growth spurt – producing elongated growth with few leaves reaching towards the nearest light source.
Plants have special proteins called photoreceptors in their leaves and stems that are very sensitive to light.
This is how they know in which direction to send their emergency growth. If the plant manages to reach the light before it runs out of energy, it will produce leaves and begin to grow normally.
Young Avocado plants can grow happily in a small pot for up to a year. After that, the roots will fill the pot, and the plant will become pot-bound.
The plant will stop producing many leaves and spurt upwards with leggy growth. This is because the overcrowded roots can’t take in enough nutrients in the correct proportions.
Too much nitrogen can cause a plant to put on a lot of growth too quickly. Nitrogen is responsible for the growth of the green parts of a plant and is necessary for healthy development.
However, when a plant receives too much nitrogen, particularly when it is not fully mature, it will produce cells at an unsustainable rate – resulting in weak, leggy growth.
Avocados are tropical or subtropical plants that like a warm, fairly humid environment with a warm summer and a slightly cooler winter.
Depending on the variety, they thrive best in temperatures of 68-82°F (20-28°C) with a humidity level of 45-65%.
Outside of these conditions, the plant is unlikely to do well and may produce leggy growth, particularly when young.
Higher temperatures are more likely to cause leggy growth spurts than lower temperatures, as Avocado plants become dormant during cooler parts of the year.
How to Fix A Leggy Avocado Tree
Provide Enough Light
The first step in fixing a leggy Avocado plant is making sure that it has enough light. For an indoor plant, it’s probably going to need the brightest spot in your home. A spot a couple of feet away from a sunny window should be perfect.
In spring or summer, if temperatures are routinely around 68-82°F (20-28°C), consider moving your plant outside. You can leave it outside at night as long as the temperature doesn’t drop towards freezing.
Mature Avocados love the full sun, but direct sunlight can burn younger plants, so if your plant is less than five years old, avoid placing it in a position where sunlight falls directly on its leaves.
This is especially dangerous near windows, as the glass intensifies the sun’s rays – burning the plant very quickly.
You’ll easily be able to tell if your plant’s legginess is due to lack of light as the growth will lean noticeably towards the nearest light source.
On the other hand, if the plant is growing straight upwards, something else is probably causing the legginess.
Prune Your Avocado Regularly
Even in ideal conditions, if you neglect to prune your Avocado plant, it is likely to become leggy. Proper pruning is essential to encourage branching. Trim the plant’s tip and topmost leaves when it’s 12 inches (30 cm). Thankfully, pruning Avocado plants is simple. Just follow these steps:
- First, get hold of some decent secateurs. These will enable you to prune your plant without causing unnecessary damage to the stems. Even very sharp scissors will cause bruising and damage the cells around the cut.
- Next, clear your secateurs of any visible debris to reduce the likelihood of spreading disease to your plant. Use a general-purpose cleaning solution. There’s no need to try to ‘sterilize’ them with bleach or alcohol.
- Now you’re ready to prune. If it’s your plant’s first pruning, make sure that the plant is at least six to eight inches tall. Make a clean cut around halfway, just above a leaf node. Leaf nodes are easy to spot – they’re the little bumps that produce the leaves.
- The plant will now produce two branches from the site of the first pruning. Once these branches are eight inches long, you can pinch out or prune the tips.
- One branch will likely take over the role of ‘main stem’ (known as apical dominance). When this stem reaches 12 inches, pinch out or prune the tip to redirect the plant’s energy into the other branches.
- Continue pruning branches whenever they reach more than eight inches until your plant is the shape that you want it. Leave smaller branches alone.
As your plant matures, you can reduce how often you prune it. Once it is around two years old, you’ll only need to prune it once a year. Make sure to do this in late fall or winter when the plant is not actively growing. (Source: University of Georgia)
Use A Suitable Pot Size
If you’ve grown your Avocado plant from seed, you can keep it in a six to eight-inch pot for the first year or two. Once it reaches two or three feet, you’ll need to repot it.
Use a pot an inch or two wider and slightly deeper. After that, your plant will need repotting into a slightly bigger pot every year or so until it has reached the size that you want it.
Once the plant is as large as you want it, stop repotting it into bigger pots. Instead, every spring, replace the top couple of inches of potting mix with the fresh mix, and every couple of years, prune the plant’s roots when they become root-bound.
Prune The Roots
Root pruning is a great way to keep a plant at a particular size without it developing problems from being rootbound. Do this once a year when your plant has reached your desired size.
- To prune a plant’s roots, gently remove the plant from its pot as you would repot it, then using clean, sharp scissors or secateurs, trim one inch from the roots of one side of the root ball. Make a note of which side you trimmed, perhaps with a mark on the pot.
- Add a little extra fresh potting mix, then place your plant back in its pot.
- After pruning a plant’s roots, always give a light prune to the top growth too to make up for the root loss.
- The next year, repeat the procedure on the other side of the root ball.
Repot Using The Right Soil
Avocado plants like a loose, fertile, well-draining potting mix that is consistently moist but never soggy.
A mixture of one-third compost, one-third sand, and one-third perlite or vermiculite is ideal. You could also use a cactus potting mix enhanced with a little compost.
Good drainage is vital to keep your Avocado’s root system healthy, so it can absorb nutrients properly and grow healthily.
The roots can easily rot if you let them stay very wet for even a couple of days, so always make sure that water can easily drain from your plant’s pot. Never leave the plant standing in water for more than an hour at a time.
Maintain The Correct Temperature Around Your Avocado Plant
It’s best to keep your plant in a situation where the temperature doesn’t vary too much and does not exceed 82°F (28°C).
Keep your plant away from heat sources and draughty areas, and try not to move it around too much.
For example, if you want to move it outside, only do it once the nighttime temperatures are well above freezing, so you don’t have to keep bringing it indoors.
When you bring your plant inside for the winter, try to do it when the temperature is similar to that inside your home to avoid stressing the plant.
Propagating Your Plant
If the idea of pruning your Avocado sounds like a bit of a pain, take comfort in the fact that you can grow new plants from the cuttings!
When you have a cutting of five or six inches, it is ideal for propagation. The process is easy:
- Remove all but the top two or four leaves from the stem.
- Scrape the skin away from the bottom ½ inch of the stem.
- To increase the chances of the plant taking root, apply the rooting hormone.
- Place the cutting securely in an equal mix of perlite and peat moss and water well.
- Keep the cutting moist by loosely covering it with plastic.
- Watch out for new growth! When you see it, you have a new Avocado plant.
Can I Cut The Top off My Avocado Tree?
In most cases, you can. Removing the top of your plant will encourage it to grow outwards rather than upwards and is an excellent way to reduce legginess.
When you cut the top off your plant, make sure to leave some leaves on the plant so that it can produce food.
If you take the part with all the leaves off the plant, it won’t be able to photosynthesize and is likely to die.
While it is possible that the plant will have enough energy stored to produce new leaves in this situation, it’s a significant risk.
How Do I Make My Avocado Bushy?
To encourage your Avocado tree to branch out and develop a more bushy habit, you’ll need to prune it regularly during its first two years, as this is when it develops its formative growth.
If your plant is older than this, you probably won’t be able to significantly change its shape or growth habit.
If you have a young plant, prune it for the first time when it is six to eight inches tall. Remove half its height, then remove the tip and top few leaves when the central stem grows back to 12 inches.
When new branches reach eight inches, remove their tips. Repeat this process with each new branch until the plant is as bushy as you want it.
As your Avocado tree grows, focus on pruning the top branches and leave the lower branches alone.
This will encourage the tree to grow laterally rather than vertically and allow more light to reach the lower leaves. Once the plant is established, an annual pruning in fall or winter will keep it in shape.
How Do You Thicken an Avocado Tree Trunk?
The best way to get your Avocado to develop a thick, sturdy trunk is to make sure it has the conditions it needs and to keep pruning the plant.
When you prune the main stem and other branches, the plant will put energy into its remaining growth – including the main stem. As the plant matures, its main stem will thicken and become more ‘trunk-like.’
The key to growing an attractive, bushy Avocado tree is providing it with the right conditions. Most importantly enough light and consistent temperatures – and pruning it diligently in its first two years.
Avocados will reward you with years of beautiful foliage if you treat them right!