VEGETABLE PRODUCTION IN NEW ZEALAND

New Zealand lies across the prevailing westerlies of the South Pacific between latitudes 34° – 47°S. The mountainous ridge along the centre of both islands creates two very distinct climatic zonings: the western side, where rainfall is high and reliable and temperatures equable; and the eastern side in the rain shadow where rainfall is lower and variable and temperatures show more extreme values.

The latitudinal shift southwards of the permanent high pressure belts in summer creates a situation of summer minimum rainfall in the north of the North Island.
Similarly, a penetration of storms of tropical origin into the north and east of the North Island can bring periods of very intense rains to these areas, especially in the autumn with consequent floods and crop destruction.

Sub-zero weather conditions in winter with snow are rare at low levels due to the long ocean fetch of the cold southerly winds.
Conditions do deteriorate rapidly away from the coast with many inland growing areas, especially in the South Island south of Blenheim and Nelson and on the central high country of the North Island, experiencing occasional snow falls and severe frosts.
Only small specialised areas of New Zealand can be classed as frost-free and these are mostly found in the North Island.

Sunshine hours in the main growing regions will range from 2 000–2 400 hours.

Although most crops in the past have been raised with little irrigation, the advent of greater specialisation has resulted in an increased need for irrigation in all growing areas.
In the east of the South Island the development of new areas for vegetable production has been dependent on the use of irrigation derived from a plentiful and pure ground water resource.

Symposium on Vegetable growing in the Asian and Pacific Region, XX IHC

R.A. Crowder

https://doi.org/10.17660/ActaHortic.1979.101.2