Grafted macadamia trees are a low-maintenance tree and will grow in almost any soil type as long as it is not water logged. Ensure new shoots are removed from below the graft of new plants or the root-stock will take over.  Macadamias are a rain forest tree native to Queensland Australia where their natural environment is lots of leaf ground cover. Therefore apply composted mulch regularly in summer and winter and the occasional liquid fertiliser around the base of the tree in late autumn and early spring.

Only stake young trees if necessary until the tree roots have established and remove stakes.

Frost protect young trees if frosts in the area drop to -4degrees.  Frost protection includes taping the trunk in insulation wrap from ground level to the 1st branches, building a shelter around the tree with a cover over the top and spreading mulch around the base to stop the frost freezing the soil around the tree.

The main pest in NZ is the Green vegetable bug, attacking the young nuts causing black spots on the nut kernel after extracting the oil.

The Guava Moth is a new pest that is causing concern because it causes early nut-drop before the kernel is mature. The caterpillar eats the inside of the husk which causes it to detach from the tree – but it is unable to penetrate the shell.

Long grass and seeds are known to harbour GVB, Guava Moth and harbour Rats – keep grass short or have it grazed by sheep and chickens.

Organic growers need to manage and maintain a clean orchard floor at all times and Conventional growers need to spray at least 3 times a season, 3 weeks after flowering at intervals of 3 weeks.

Dropping Varieties – No

Never cut out the centre of a Dropping variety – let them grow naturally!

In most Dropping varieties, the central leader holds the majority of the crop. Droppers are bred as ‘open’ and are naturally open to light, air and bees for pollination.  The more branches the more crops and the height of dropping varieties is not an issue because the nuts drop.  Occasional shaping in year 2-3 to remove weak branches and selective pruning of dead or weak branches only is recommended when the tree is mature.

Beaumont and other Picking varieties – Yes
Beaumont’s will stand quite heavy pruning. The aim when pruning is to keep the tree to a manageable height (3 to 4 metres), cut strong leaders out and open-up the interior of the tree to light, air and bees to help pollination.  However because Macadamias naturally flower into the centre of the tree, ensure you don’t cut out too many fruiting branches that hold your crops. In short, keep the tree low and open on the inside to aid pollination and to make picking easier.

Use this 3-step Maturity test to check when your macadamias are ready to harvest:

1. Check the inner husk lining is brown.

If the lining is brown, follow the next 2 steps. If it is white, in most cases the kernel is still immature.

2. Float the Nut in Shell (NIS) in tap water.

If the NIS floats discard as it is immature or insect damaged.

If the NIS sinks, the last step to test maturity requires extracting the kernel.

3. Crack the NIS, extract and float the kernel or kernel pieces in tap water.

If the kernel floats it is mature with 70% plus oil content – your nuts are ready to harvest.

If the kernel sinks it has insufficient oil (immature) and not ready to harvest yet.

The 3-step maturity testing is necessary for Droppers and Pickers.

Harvesting Dropping varieties

Dropping varieties will drop their nuts when they are ready, however they can be harvested off the ground OR harvested (picked) off the tree!  Yes – Droppers can be strip-picked when they are ready.

Beware though – not all Droppers are ready at the same time.

Nine new dropping varieties from Torere Macadamias Ltd, provide seasonal harvest options to suit growers lifestyles and locations, with 3 different varieties for each harvest season.

Early-season (April-June), Mid-season (July-Sep) or Late-season (Oct-Dec).

Harvesting Picking varieties

Beaumont, GT205, Own Choice and other Picking varieties are generally not ready for picking until July depending on location and climatic conditions.

Beware – nuts will pre-germinate on the tree if not picked at the right time.

1. Remove the husks preferably within 24hours of harvesting, particularly if the husks are closed.
2. Dry the dehusked nuts in drying bins with ambient air or hang in onion bags in a dry, airy, shaded location for approx. 3 months to reduce the moisture content by approximately 10-15%.
3. Store on the hot water cylinder for a minimum of 3 weeks. The additional dry out weight loss will be approximately 8%. (a dehumidifier can be very helpful)
4. Now dry and ready for cracking, the kernel will ideally be rattling in the shell and above all will be crunchy and savoury or sweet – depending on the variety.
5. WARNING – Rats love Macadamias!!! If you see empty shells with little holes chewed into them… You know you have them! Organic growers use traps and conventional growers use bait.

All nuts deteriorate over time, however Macadamias ‘in shell’ will keep well for a couple of years in a dark, cool and airy place. After cracking, the kernels will keep for about six months if kept in an airtight and moisture proof container.