The nuts that we love to eat are the seeds that the tree uses to reproduce in nature so it’s actually possible to plant a nut in a shell purchased from the greengrocer in your garden and have it grow into a tree.
Although growing a macadamia tree from seed takes time, it is a great project for enthusiastic gardeners and particularly fun for kids to try! Autumn and Spring are both great times to start.
Here’s what you need to do:
- Use fresh nuts in their shells: The kernels by themselves won’t germinate, so make sure you use a nut in its shell. Find the freshest nuts you can. Recently harvested ones are more likely to grow into saplings.
- Soak the nuts: Soaking the nuts overnight in warm water the day before you plant them lets them know it’s time to grow!
- Get the pot ready: Start with a small pot. One the size of a one litre ice cream container is ideal. Add in a good-quality, free-draining potting mix. No fertiliser is needed, as the nut contains all the goodness a young sapling requires.
- Plant the nuts correctly: To give your nut the best chance to sprout, place it 1cm below the surface of the potting soil. Look for the little white dot on the shell. Called the micropyle, this is where the nut sprouts. Ensure that it is facing to the side for best results.
- Care while growing: Place pot in a warm, sunny spot as it grows and keep the potting soil moist but not wet. To check the water level, place your finger in the potting soil. If some sticks to your finger when you take it out, it’s too wet.
- Potting into the garden: Macadamias are slow growing, so your nut will take a few months to sprout. When your sapling has grown a few sets of leaves, and its roots fill the container, it is ready to transfer to a bigger pot or out in your garden. Dig a hole in a sunny, well-draining part of the garden, just deeper than the container. Place the plant and all the potting mix around its roots into the hole, gently bedding the plant in with soil. Water well, and continue to give the plant at least two full cans of water every other day for about two weeks after transferring.
- Ongoing care: Being an Australian native, macadamia trees are well suited to our climate and require little care. Once established, you will only need to water if you live in a hot, dry area. Feed your tree with native-plant fertiliser in Autumn and Spring and mulch well.
- Macadamias don’t like frost: The subtropical rainforests where macadamia originate are frost free. If you are expecting frosty conditions, wrap the trunk of your tree to stop frost damage. Frosty leaves are less of a concern as they will grow back, but trunk damage can be fatal!
Don’t be in a rush for nuts: Your tree will grow and give habitat to birds, bees and other insects, but it may be four or more years before you get flowers that, once pollinated, become delicious nuts.