Ever wanted to make the ultimate statement of self sufficiency at Christmas time? What about sitting around the table cracking walnuts you've grown?
Whether you pickle them, cook with them, press them into oil or eat them raw, the versatile walnut is packed with energy and protein. They also have a high fat content but studies have shown that eating a few nuts every day can have great health benefits. It can reduce the chance of coronary disease, diminish the likelihood of having a stroke or developing type II diabetes, in both overweight and fit people.
Even if you only grow one tree for the family to enjoy you could be adding another couple of years to everyone's life. They also make amazing lumber trees, at around 45 years to mature to milling size it could be something you will leave to your children or grandchildren as a nest egg.
Most of our walnuts are imported from China, India or California. By the time we get them they are often old (worse still rancid), have lost flavour and nutritional value. There are good opportunities for locally grown product if it is marketed well.
Walnuts like a dry climate, with high temperatures in the summer months. They grow faster in areas with a cold winter, which makes parts of both Islands ideal. They are prone to walnut blight in areas with high humidity, although this can be alleviated by choosing a variety which will tolerate these conditions better than others.
" Walnuts prefer fertile soil with rich organic content and a moderately high PH. It helps them reach maturity earlier than when grown in poorer soil types.
" Good drainage is critical, soil should be free-draining to 2 metres, mature trees have been known to die if they sit in water for several days.
" They need good shelter to protect them against even quite mild winds while they are establishing. If you don't have good shelter you may want to consider putting in individual tree protection.
" Irrigation is important to ensure they aren't stressed during the dry summer months. The top of our year-old walnut tree died out during a particularly dry summer. While it continued to grow (about a 3rd of its original size) a good irrigation system would have eliminated this setback.
It is recommended that you start with quality grafted trees, which should start producing nuts in their first year. I temper that with expert advice that nuts should be removed from the tree for the first five years. This ensures the tree puts its energy into establishing and growing rather than into nut production.
Years of research into suitable varieties has shown that Meyric and Rex are ideal for NZ conditions. If you live in areas which aren't particularly suited to walnuts (such as Northland) check out other varieties. There may be one that tolerates your local conditions better.
Plant your trees in rows with enough room to drive a tractor between the rows. Access is further helped by pruning the branches up to a height of 2m.
Your trees should begin producing good volumes of nuts from 5 years on and reach commercial production levels by about year 10.
The trees tend to be relatively pest and disease free. Walnut blight can be an issue but regular copper sprays have been successful in combating it. Regular fertiliser helps ensure they are kept in top health. The most difficult issue you're likely to face is possums who find them most palatable.
Grass between the rows will need to be mowed and the ground under the trees will either need mowing or spraying to make nut harvesting easier.
The nuts are harvested in the autumn. They fall from the tree and are collected off the ground. They need to be removed from their husks and dried before storing in a dry dark place with good ventilation, where they will store in their shell for 3 months.
If you are going to pickle your walnuts pick them from the tree when they are green (unripe) and the shell hasn't formed - usually around December/January.
From harvest you can either supply a number of processors around the country or sell them directly to the public at your local Farmers Market. You may want to add value, and increase your returns, by processing them into pastes, pickling them, pressing them into oil or developing your own authentic recipes.