Unlike other tree nuts, macadamia trees are not shaken to make them give up their crop. The macadamias fall naturally to the ground when they are ready and are collected by mechanical harvesters, with spoked wheels, which roll over the nuts and pick them up for de-husking on the farm.
Even though macadamias have a high oil content, over 80% is the good monounsaturated fat which is very healthy and may even help reduce the risk of heart disease. Eaten in moderation with a balanced diet, macadamias are unlikely to contribute to weight gain.
Nut development in macadamia from full flowering (anthesis) to kernel maturity takes about 30 weeks. Anthesis in the last week of September would be followed by an exponential increase in growth at 4-7 weeks (October/November), and shell hardening in 14-15 weeks (end of December) at which time cell division is complete and no further growth takes place. For the next three months (January to March) nuts mature by converting sugars and starches to oil. This is a very important process which determines the final quality of the nut.
It is important to buy good quality planting stock when establishing an orchard. Avoid trees that are stunted, root bound or infested with pests or infected by disease. To ensure the orchard gets off to a good start, select vigorously growing trees free from nutrient disorders, insect pests and disease with a good healthy root system.Buyers should look closely for:
For varieties which do not drop their nuts (Beaumont), the simplest way is to look at the lining of the husk after the shortest day of the year. When the lining has turned deep brown, to about the same colour as the nut inside, the crop is ready for picking. Depending on the weather and position of the trees this can be as late as one to two months past the shortest day. Beware, trees can drop (abort) quite a lot of nuts if stressed by drought, these nuts will be immature and can be mistaken as ripe.
Macadamias are a low maintenance tree and will grow in almost any soil type as long as it is not water logged. It is a forest tree native to Mt. Kenya and likes a good mulch. The main pest in NZ is the green vegetable bug, attacking the young nuts and causing black spots on the nut kernel. Long grass and seeds are known to harbour these bugs, keeping grass short or having it grazed by sheep will help. Organic growers and the majority of smaller growers take the risk of loosing some of their crop, in a bad year up to 30%, by not spraying . If you decide to spray, then 3 times a season will do the job, starting 3 weeks after flowering at intervals of about 3 weeks.
None ... Like all tree nuts, macadamias contain no cholesterol. In fact, medical research has shown that eating a small quantity of macadamias each day may even result in a decrease in the levels of the harmful LDL cholesterol without affecting the levels of the good HDL cholesterol. In fact there has been some very interesting research done by the University of Newcastle on the health benefits of macadamia nuts. Please follow this link to The American Society for Nutritional Sciences, Journal of Nutrition. 133:1060-1063, April 2003 to read this ground breaking article. http://jn.nutrition.org/cgi/reprint/133/4/1060.