Every year when avocado season swings around I end up with jars with avocado pits in a variety of states of sprouting all over the place. It’s just so much fun to watch them grow.
It’s pretty simple but you’ll need a fair bit of patience!
Choose Your Avocado
Don’t worry about how the avocado you get the seed from tastes. Avocado trees grown from seed rarely grow fruit and if they do it won’t be like the parent avocado. Instead, try and get one from a healthy, ripe avocado. Overripe is even better. I have less luck with smaller underdeveloped seeds so keep an eye out for a decent sized one.
Sometimes you’ll get lucky and the seed will have already started to grow inside the avocado!
Harvest the Seed
Cut the avocado open around the middle. The important part of the seed in the bottom so cutting around then centre means you won’t end up accidentally damaging it. Open it up and dig the seed out.
Clean the Seed
The seed will be a bit slimy so give it a wipe with a paper towel or a rinse under the tap until you can grip it (or hold it wrapped in a paper towel) without it popping out.
Top vs Bottom of an Avocado Seed
The roots grow out of the bottom of the seed and seeing as the seed is only going to be partially submerged you need to make sure that the bottom is in the water.
It’s pretty easy to tell. Look at the seed side on and the thinner, pointier end is the top. The fatter, flatter end is the bottom.
If you’re not sure then check out the two ends. The top will be smoother. The bottom will have a nubbly looking bit.
Peel the Seed
A lot of people peel their avocado seeds but, that brown coating works as protection from the sun. If you’re going to have it outdoors in direct light or on a very sunny windowsill then you might be better leaving the skin on so the seed doesn’t get sunburnt and shrivel up.
If it’s going in bright indirect light then peel it off – the water breaks it down after a while and starts to fall off and look a bit gross. Peeling can be a bit tricky. Use your fingernails or a knife and try and break the skin. Sometimes the skin on the bottom will be a little loose so be careful. Once you’ve managed to make a hole in the skin, peel it off like you’ve just put glue all over your hand in school. Try not to damage the seed especially the fatter bottom end.
The skins in two layers, a smooth, brown outer layer and a veiny, brown under layer. Sometimes the skin’s really stuck to the seed so if it won’t come off don’t worry about it. It’ll come off on its own when it feels like it.
Next, we’re going to jab some toothpicks into the seed so we can balance it on a glass. I use three toothpicks and you don’t need to push them in very deep. Just deep enough so that they’re secure. Stick them about a third of the way from the top of the seed (the thinner pointier end) into the flat parts of the seed – avoid the craggly looking lines.
I angle mine upwards a little so that the seed hangs down into the glass so that it’s a bit protected.
Setup Your Jar
Using transparent glasses and jars aren’t the best choice for sprouting anything. It lets sunlight in which can cause algae to grow. But…what’s the point of sprouting things in water if you can’t get a good look at all those lovely roots!
So, grab a jar, a glass, a something-that’ll-hold-water and balance your toothpick avocado thing on the top so that the bottom (fat end) of the seed is hanging into the glass.. Fill it up with water so that about a third of the seed is submerged.
Caring for your Seed
Pop the whole thing somewhere warm with bright indirect light or full sun (if the seed still has the skin on).
Change the water every few days. Water contains oxygen and the amount of oxygen in the water decreases over time. Aside from that, the water can get a bit nasty if you leave it for too long and things might start looking a bit green and murky if you don’t.
I give my avocado seeds about 6 – 8 weeks to show signs of life. It’s definitely worth planting more than one seed – if you end up with more than you want, they make fun little gifts especially for kids.
Sprouting your Avocado Seed
At some point, if the seed’s alive, it’ll start to split open. It usually starts at the bottom as a little crack and it’ll grow over the next week or so.
Then, after a while, a fat little white root will poke its head out of the bottom from the crack.
Sometimes, like with this seed, you get a root and no crack!
That root is the tap root. It’ll keep growing straight down until it finds an obstacle. When it gets big enough it’ll start to put out more and more roots until it looks like some squid alien type thing.
Moving your Avocado Seed to Soil
As soon as you see that root appear, it’s the perfect time to get it into soil. Like you saw in the picture further up, they can grow quite big in water and they transfer pretty well to soil so you could leave it in water longer. However, the larger the root system, the harder it can be to get it into soil without damaging it. Especially the tap root with is delicate and easily snapped. I’ll cover how to pot up larger root systems in the next section.
Fill a 6-inch plastic pot up with regular potting soil leaving an inch or so of space at the top and pat it down. Avocado seeds need to be sticking out of the soil. The seed protects the trunk from being in constant contact with the wet soil until it’s large enough to handle it.
Dig a shallow hole in the middle of the soil, it should be deep enough to bury the seed about a third of the way up. Carefully pull the toothpicks out, because the seed’s cracked if you squeeze it it might break. Gently put your seed in the dent and don’t push it down – pushing it down could damage the root.
Water the soil around the seed really deeply which will help move the soil around under the seed so that it makes good contact with the root. If the soil level goes down then sprinkle some more around the seed.
Pop it in bright indirect light for a week while it adjusts to its new environment then move it back to whatever light conditions it was in before.
Keeping the soil moist is important at this stage. Don’t leave it in standing water and don’t keep it waterlogged or the seed might start to rot. Water it whenever the top layer of soil starts to dry out slightly – it will go a slightly lighter colour but still feel damp to the touch.
Moving an Avocado Seed with Long Roots to Soil
If your avocado seed has one long tap root then follow the instructions above but, when you make the dent for the seed, use a chopstick to make a nice wide hole for the tap root to slip into. Make it much wide than the root so you don’t accidentally knock the root on the soil. When you water it, the soil will jiggle around the root and fill in the space. Once the seed’s in place, don’t pat the soil down or anything like that.
If you’ve got a full on root system then pop some soil in the bottom of a pot that’s an inch or two bigger than the roots. Hold the seed over the pot at about the height it’ll be in the pot and start scooping in dry soil. Dry soil is lighter and less clumpy than wet soil so it’ll fill in the space around the roots easier. Once the soil’s at the level you want, keep a hold of the seed and water the soil. The soil level will go down so keep on scooping in soil and watering it until it comes up about a third of the way up the seed and the soil supports it. Don’t pat the soil down because it could damage the roots.
Sprouting your Avocado Seed (Part 2)
We’ve got roots, now we need some leaves! It can take a while for the stem to start making an appearance – I told you you’d need a lot of patience. It’s well worth it though. They make really lovely houseplants.
The stem grows from the point in the seed where the root is attached (about two thirds of the way down) and if you’ve got a decent crack sometimes you can peek in there and see it growing. If not, you’ll have to wait til it hits the top of the seed.
Keep on watering it and keep an eye on the delicate new leaves for any signs of problems like sunburn.
Getting Your Avocado Tree to Branch
Avocado trees are tall so getting it to branch early is important. It’ll give you a nice bushy plant instead of loads of trunk.
Once it’s got a few small leaves, pinch out the growing tip. The growing tip is where it’s forming new leaves. When you take out an avocado trees growing tip it’ll try to find a new way to grow. Usually that means you’ll get two or three new growing tips which will turn into branches.
Once in a while, it’ll send out one new growing tip and continue to grow straight upwards. If that happens you can either wait for it to grow a few new leaves then pinch out the growing tip and keep your fingers crossed that it works this time. Or, you could but lower down the stem. As long as there is a leaf and a node or two (the nobbly bit on the stem where the leaves grow) then it should be ok.
Moving it to Full Sun
With skinless seeds, you need to wait until the leaves are large enough to shade the seed.
I have mine in a spot where they’re getting a few hours of direct light a day and they’ve got a darker almost rosy tone to them. But, they seem happy enough. They haven’t shrivelled up but keep an eye on them if you’re introducing direct light before it’s got some shade leaves.
Avocados love full sun but, it’ll need to hardened off first or the leaves will burn. Start with an hour or so of more intense light and watch out for signs of stress like wilting or the leaves starting to feel thinner than usual, browning leaves, yellow or white patches or leaves curling up. In other words, if it’s appearance starts to change then abort the mission. Get it back to its usual environment to recover.
If your plant was fine then try two hours the next day. Then three the next and so on until it’s getting as much as it needs – 6 hours a day minimum. As you saw with my avocados wonky little trunk, you’ll need to rotate it once in a while if it starts growing towards the light.
Avocados are thirsty plants so you can cut back on watering a bit. Once it’s pushed out the trunk the root system should be deep enough to withstand the soil drying out a little more. I let the surface of the soil dry out a little more, it goes a little lighter but not completely dry, then. give it a really good water.
Avocado plants are sensitive to salt buildup in the soil – a common symptom is brown dried up leaf tips. It’s better to use water that’s been sitting out all night so that some of the chemicals can evaporate out. Unfortunately, it won’t get them all.
To help prevent salts from building up make sure that when you water it make sure the water comes flowing out of the drainage holes. I bottom water mine once in a while by standing it in a bowl of water and letting it wick up as much as it wants. Bottom watering gives the salts time to dissolve. Then, once you take it out of the water top water it and let the water come out of the drainage holes for 10 seconds or so to flush the salts out.