How to grow an avocado from seed
1. Remove and clean the pit
When cutting your avocado open, take care not to cut the seed. Remove it from the avocado and wash it well, removing all of the fruit's flesh. Anything left will turn to mould. But be careful not to remove the brown skin covering the seed.
Offering some helpful tips, Ashley Webster from All Green Nursery says, "Look for a seed that is plump, without any cracks or blemishes. It should also feel heavy for its size."
2. Figure out the top and bottom of the avocado
While the size and shape of avocados can vary slightly, they all have a top and a bottom. The pointier end is classed as the top, and the flat end is the bottom, where the roots will emerge. The top will sprout the shoot. This is important to know when submerging the seed in water.
3. Pierce the seed with three toothpicks
Next, it's time to submerge the bottom half of your avocado seed in water. You will need three toothpicks to balance the seed over the water so only the bottom half is submerged.
Stick the toothpicks into the seed at a slight angle, evenly spaced around the seed, allowing the bottom half to immerse in water.
"Make sure about 2cm of the seed is submerged," says Ashley.
If you want to skip the toothpicks, avocado seed-growing kits are also available to make the process easier.
4. Regularly change the water
Keep the water level consistent and change it every few days to prevent mould. The top should remain dry.
5. Wait for your avocado plant to grow
Place your jar in a warm, sunny spot (away from direct sunlight) and wait for your avocado seed to grow. You should see signs of life in around two to eight weeks, with some roots growing out the bottom. A leaf should start to grow out of the top of the seed at about eight weeks.
This is a quick rundown of what you can expect to see in the process:
- Initially, when the avocado seed is suspended in water, the seed starts to crack, and little taproots emerge from the bottom. The brown skin will also fall off. This is the early stage of the seed absorbing water and preparing for germination.
- After a few weeks, a tiny sprout will emerge from the top of the seed. This is the shoot, indicating the seed is ready to transition to the next growth phase.
- As the shoot grows, you'll notice the development of leaves.
- Once the roots are around 5-8 cm long, it's time to transplant the avocado seed into the soil. This marks a crucial transition where the seedling shifts from relying on water to drawing nutrients from the soil.
6. How to plant your avocado seed
Once the root is about 5-8 cm long, transfer your avocado plant to a small pot with well-draining soil.
"You'll want to use a well-draining potting mix," says Ashley, adding, "It should be a mix of soil, sand, and organic matter. This soil type will help prevent waterlogging and provide good aeration for the roots. You can also add some perlite or vermiculite to improve drainage."
Dig a small hole in the soil, then carefully insert the seed with the root side facing downward. Cover the seed with soil, ensuring that the top part of the seed remains visible.
Water the soil, making sure you don't overwater the plant. "Place the pot in a sunny spot and keep the soil moist but not soggy. Avocado plants love sunlight!" says Ashley.
How to transplant your avocado plant
Once your seedling reaches around 15-25cm tall and has a strong root system and a few sets of leaves, you can transplant your avocado seed to a pot using a well-draining potting mix enriched with organic matter.
"Choose a pot slightly larger than the current container to allow room for growth. Make sure the pot has drainage holes to prevent waterlogging," says Ashley.
To transplant your seedling, gently extract it from its container without harming the roots. Transfer it to the new pot, ensuring that the plant crown aligns with the soil surface as you fill in with soil.
Give your plant good water and place it in a nice sunny spot (away from direct sunlight). "Monitor the soil moisture and water when the top centimetre feels dry," says Ashley.
How to germinate avocado seeds in a paper towel
Germinating an avocado seed in a paper towel can often be faster compared to placing the seed in water. Here's a simple guide on how to grow an avocado seed using a paper towel:
- Clean and prepare the avocado seed using the same steps above.
- Place the avocado seed in a damp paper towel, folding it over the seed, ensuring it's completely covered.
- Put the covered seed in a zip-lock bag, seal it and place it in a warm, sunny spot away from direct sunlight.
- Once the avocado seed has sprouted a root, submerge the bottom part in a glass of water, keeping the top dry and watch your avocado seed grow.
How to grow an avocado tree that bears fruit
Unfortunately, there are no guarantees your avocado plant will grow fruit. Some say it will after three to four years, others say 15 years, and others never. Either way, it's a good-looking plant around your home.
"Avocado trees are usually propagated through grafting, combining the desired fruit-producing variety with a rootstock that provides strong roots. This method ensures that the resulting tree will have the same characteristics as the parent plant and is more likely to bear fruit," Ashley explains.
"While it's fun to grow an avocado plant from a seed as a gardening project if you're looking for an avocado tree that reliably produces fruit, it's best to obtain a grafted avocado tree from a nursery. That way, you'll have a higher chance of enjoying delicious avocados in the future!"
Avocado growing tips
How often do you need to water an avocado plant?
Water the plant whenever the soil's surface feels dry, but be cautious to prevent it from drying out completely or becoming waterlogged.
How to prepare the soil for planting an avocado tree
Avocado trees need a well-draining potting mix that is rich in organic matter.
Does an avocado tree need full sun?
Avocado seeds thrive in sunlight, so position them in a well-lit area with a minimum of 6-8 hours of indirect sunlight daily. If natural sunlight is unavailable, Ashley says you can use a grow light to ensure they receive the required light.
When is the best time to plant an avocado tree?
Avocado trees flourish in warm climates, ideally with temperatures ranging from 15-29°C. They require well-draining soil and ample sunlight. Consider cultivating avocados indoors or in a greenhouse if you live in a colder climate.
Best soil pH for an avocado tree
Avocado trees thrive in soil that leans slightly towards the acidic side, ideally having a pH of around 5.5.
How do you pollinate an avocado tree?
Bees and other insects usually cross-pollinate avocado trees. Ashley says, "If you have multiple avocado trees nearby, there's a better chance of successful pollination and fruit production. However, some avocado varieties are self-pollinating, so you may still get fruit even with just one tree."
Pruning and shaping your avocado tree
As your avocado plant develops, trim it to encourage a more bushy form. "This helps promote a stronger structure and better fruit production in the future. Just be careful not to prune too much, as it may stress the plant," says Ashley.