Growing Macadamia Nut Trees
Now, while Macadamias are not at all difficult to grow from seed, there is a degree of patience required for success. We sell our seed nuts (intact) as this will guarantee at least seven years of viability before planting. Fresh nuts are not ready to germinate, so all of our seed is at least 6 months old.
The seed can be planted intact and simply left to germinate of it’s own accord. This is guaranteed to succeed as long as you are patient and willing to allow the seed to germinate as nature intended. Your potting mix must be reasonably course. This will ensure that the seed does not rot while it is waiting to sprout. Ours always germinate in a mixture of mulch and sand, up off the ground on a stand, and watered weekly. To speed things along, you can scarify the seed coat to allow some moisture to penetrate the polished seed shell.
Cracking the outside casing is never the best method as it can damage the seed or simply provide access to insect , animal or fungal attack. We use a bench grinder to simply remove the ‘polish’ from the seed coat in one small area only. You can just as easily use a file to achieve the same result. Once the seal has been broken on the case, it can begin to absorb moisture at a natural rate and therefore signal to the embryo that it is time to get active. It seems very important not to help the seed escape it’s hard coating.
Almost as a right of passage, the growing seed must have the strength to break it’s way out to therefore become a robust plant. Seedlings that are helped along become weaker as time go by. Once you have achieved germination do not shower the seedling with fertilizer, it does not need it yet. The seed is quite able to supply enough energy to the emerging seedling.
Wait until you have at least four leaves on your seedling before applying a slow release pellet fertilizer.
Macadamias are quite tough and can be planted out when only 20 cm high.
Once again, these are a long lived tree, so don’t be impatient anual supply and will encourage the plant to spread.