Grow an avocado plant from a seed
Growing an avocado tree from a seed is a really fun project. The seed is so different to the seeds of a lot of the plants we usually grow and because they are so big, you get a really good view of what happens when the avocado seed germinates. You can, of course, plant your avocado seeds straight into soil and they will grow well but by germinating them in water, you will be better able to see the fascinating process of the seed splitting, roots developing and the stem emerging from the seed.
What you will need:
Avocados
Kitchen towel or a small cloth
Lidded container
A clear glass, jam jar, small vase or bottle full of water
Toothpicks
Eventually you’ll also need a plant pot and some potting soil
What you need to do:
The germination rate for avocado seeds is pretty high, but not 100% and so it’s worth trying to germinate a few seeds to avoid disappointment!
First you’ll need to remove the pits from the avocados and then give them a good wash. Be careful not to cut the seed when you cut the avocado open.
Use your fingernails to peel off the brown skin. This isn’t essential but can speed up the germination process, particularly if the skin is thicker or harder (and unfortunately, this makes them harder to peel!). You can soak the pits in a bowl of warm water for a few hours to make this a little easier.
From here, you have two options and you could try both methods if you have more than one avocado seed:
The toothpick method:
The first option is to suspend the seed over a jar of water. To do this you’ll need to identify the top and bottom parts of the avocado pit. You will notice that it is almost tear-shaped. The bottom part should be slightly flat and this is where the roots will grow.
Push three toothpicks equidistant from each other into the seed at it’s widest point. Try and angle the toothpicks slightly so you are pushing them downwards into the seed.
Fill your glass or jar with water and then suspend the avocado seed over the water by resting the toothpicks on the rim of the glass or jar. The water should cover about a centimetre of the pit at the base.
Put your glass on a warm and bright windowsill. Make sure the bottom of the seed is always kept submerged in water and change the water once a week.
The wet cloth method:
The second option is to wrap the peeled avocado seed loosely in a wet cloth or paper towel and then put it into a sealed container and leave somewhere warm. This is a slightly quicker and more reliable method to germinate your seed.
Check on the seed once or twice a week and swap the wet cloth or kitchen towel for a fresh one to make sure it stays moist and to help prevent it getting mouldy.
With both methods, the first thing you’ll notice in about two to four weeks, is the seed beginning to crack open and a split appearing. This is an indication that a root is starting to form and will soon emerge from the base. If you look closely, you’ll be able to see the root and maybe the stem inside the crack!
If using the wet cloth method, then once the root is about an inch long, you can transfer the seed to a clear glass, jam jar or small vase using the toothpick method above so that you can watch the avocado plant grow. If you have a vessel with a narrow neck such as a bottle, you might be able to simply rest the avocado seed on top of it without using toothpicks like I did.
In the next week or two you should see the tap root grow down into the water and even send out root offshoots.
After another week or two, you should see a stem start to sprout from the top of the seed and then leaves will start growing. Once they’ve got going, they grow pretty fast!
In these early stages of growth, keep an eye on the water level as some of the water will evaporate, so your root may not be touching water and may dry out.
Once the stem is about 30 cm long, then it will need to be potted up so it can get nutrients from soil. You’ll need a container with good drainage holes and well-draining potting mix.
To transfer your seed into a pot, first add a layer of potting soil to the bottom of your chosen container. Hold your avocado seed in the centre and with the top of the seed approximately level with the top of the container and then backfill with your potting soil. Firm the soil around the roots and bury the seed about halfway, ensuring that an inch of seed remains above the surface. Water well.
With a sharp pair of scissors or snippers, cut the avocado stem above a node so the remaining stem is about 15-20cm tall. Nodes are easy to identify, anywhere a leaf is growing out of, even those tiny ones up the stem, are nodes.
Don’t worry that this seems drastic as it will help the avocado tree grow stronger and encourage bushier growth!
Put your avocado plant somewhere with bright, indirect light and water regularly.
Pinch off the newest leaves every time the stems grow another 15cm or so to encourage more growth and a fuller plant.
As it grows, your avocado will require added nutrients just like any other plant. You can use fertiliser or fresh compost, adding it to the soil once each spring, summer, and autumn. It will go dormant in winter, so you won’t need to fertilise it during that time.
It’s a good idea to do repot your avocado tree into a larger pot at least every year. The bigger your pot, the bigger your tree will grow!
Author: Denise Hope, home educating mum of two boys
This activity was part of a previous Mud & Bloom box. If you’d like to receive regular activity ideas like this, along with nature craft and gardening activities for children, subscribe below to receive a monthly Mud & Bloom box!