The New Zealand Vegetable Produce Growers' Federation, the national organisation, is supported by a levy on produce sold at auction or to processing firms. This is collected under the terms of the Vegetable Levy Act 1957. District associations of growers are organised into two groups within the federation, one serving the interests of market-vegetable growers and the other being concerned with the process-vegetable growers.

by Iain Gordon McKenzie Forbes, M.AGR.SC., Horticultural Division, Department of Agriculture, Dunedin.

The Horticulture Division of the Department of Agriculture advises vegetable producers. The advisory staff in most main producing areas is backed by specialist officers in laboratories and experimental areas. District experimental and demonstration work is an important part of the advisory service and is carried out on growers' properties, as well as on experimental areas at Avondale, near Auckland, and at Invermay, near Dunedin. The Horticultural Research Station at Levin deals mainly with vegetable research. The Crop Research Division of the Department of Scientific and Industrial Research carries out plant breeding and selection at Otara, near Auckland, and at Lincoln. The Plant Diseases Division, Department of Scientific and Industrial Research, at Auckland and Lincoln provides a diagnostic service for pests and diseases and, as well, studies diseases and pests of vegetable crops and means for their control. Other scientific work is carried out by Cawthron Institute, in Nelson, and the Agricultural College at Lincoln and Massey University of Manawatu.

Most fresh vegetables are sold at auction markets. Glasshouse tomatoes may be carted long distances, often between the two Islands. There is little inter-Island trade in bulky vegetables, apart from potatoes, onions, kumaras, and pumpkins.

Most market vegetables are packed in cases or sacks. The Samoan banana case is much used. There is some prepackaging, principally of celery, but washing and prepackaging of produce are not yet popular.

Warm humid weather in northern districts encourages outbreaks of fungous and bacterial diseases. Late blight of potatoes may come at most times of the year at Auckland and Pukekohe, and in all parts of New Zealand if the weather favours it. Frequent spraying is essential in the north. Spraying in the south is done according to seasonal conditions. The main fungous diseases are soil-borne fungi in glasshouses and in seedbeds, late blight of potatoes and tomatoes, botrytis rot of a wide variety of vegetables, and leaf-spotting diseases of celery and lettuce. Bacterial diseases have become more troublesome since fewer copper sprays have been used. Virus diseases are common, particularly in potatoes, tomatoes, brassicas, lettuce, and legumes. Many virus diseases are spread by insects, chiefly aphids, thrips and leaf hoppers. Troublesome insect pests include aphids, caterpillars of the white butterfly, tomato moth, the silver Y moth, and cutworms. All of these cause much damage in some seasons. Soil-borne nematodes occur in many areas (see alsoInsect Pests).

According to the 1956 Census, 60 per cent of the 563,052 inhabited private dwellings had a garden. Some gardens provided the following proportionate vegetable needs (other than potatoes).

(New Zealand Official Year Book, 1964)

Tomatoes are the most important glasshouse crop, taking up over 8 million sq. ft. of the total glasshouse area of 8.9 million sq. ft. (Department of Agriculture estimate). Other main glasshouse crops include cucumbers (0.46 million sq. ft.), French beans (0.083 million sq. ft.), grapes (0.405 million sq. ft.), and lettuce. Auckland has the largest area of glasshouses (2,834,800 sq. ft.), followed by Christchurch (1,152,838 sq. ft.) and Nelson (1,387,000 sq. ft.). There are commercial glasshouses in most districts of New Zealand. About 40 per cent of glasshouses are heated.

Glasshouse production units are small by English and European standards, the average being four to six glasshouses. Single-span 30 ft × 100 ft glasshouses are preferred, heated mainly by hot water, though hot air heating is coming into favour in some districts. Trickle irrigation is popular because it saves time in watering and feeding and helps to control plant growth and development more closely. The soil is usually sterilised each year by steam or special chemicals. Some southern growers who have difficulty in using chemical soil sterilants because of low soil temperatures resoil their glasshouses annually. Paint-spray equipment is used extensively to apply therapeutants.

Mechanisation is on the increase. Process-pea growing is completely mechanised, but some other crops still need much hand labour. Even small market gardens are making more use of engine-driven equipment for cultivation and crop protection. Very few horse-drawn implements are used.

Quick freezing has expanded remarkably since the end of the Second World War. The increase has been partly due to an export sales drive, but principally to greater consumption in New Zealand. There are now food cabinets in most food shops, supported by a well developed distribution service which provides a wide choice of frozen vegetables at all times of the year. The Heretaunga Plains, around Hastings, support a diversified processing industry and produce over half of the total. Other main areas are centred on Auckland, Gisborne, Nelson, and Christchurch. The main crop grown is peas, followed by French beans, tomatoes, sweet corn, and asparagus. Broad beans, cauliflower, Brussels sprouts, carrots, parsnips, beetroot, spinach, sprouting broccoli, and onions are all grown for processing, and the winter crops are important in extending the processing season.

In 1956–57 the processers produced 27,000 tons of vegetables and tomatoes; this grew to 34,000 in 1957–58 and 51,000 in 1963–64. The value of frozen vegetables exported was £300,000 in 1957, rising to nearly £400,000 in 1959, and £730,000 in 1963–64. The value of canned vegetables exported fell from £387,000 in 1957 to £130,000 in 1962–63.

Accurate statistics of outdoor vegetable production in New Zealand do not exist. In 1962 the Department of Agriculture estimated that there were 2,770 growers gardening 36,500 acres. Processing firms are estimated to have used produce from approximately half the total acreage to meet the mounting local and export demand for processed vegetable products (New Zealand Department of Agriculture Annual report of 31 March 1963). These are the main vegetable-growing districts: Auckland, 1,928 acres; Pukekohe, 5,734; Hastings, 8,802; Levin-Otaki, 975; Nelson, 2,900; Christchurch, 2,383; and Dunedin, 1,061.

Market gardening has tended to be concentrated on fertile, easily worked soils. Silt-loam soils have been preferred, but lighter and heavier soils and peat soils have also been used. In the North Island recent alluvial soils near Hastings, Gisborne, Palmerston North, Levin, and Otaki, and in the Hutt Valley and at Greytown are used. Brown granular clays or yellow-brown loams of volcanic origin are used near Auckland, Pukekohe, Hamilton, and Ohakune, and in the Bay of Plenty. Peaty soils are used at Opiki and in the Bay of Plenty. In the South Island recent alluvial soils are used near Nelson, Motueka, Blenheim, Christchurch, Willowbridge, Balclutha, and on the Taieri Plains. Peaty soil is used at Marshland, in Christchurch. Vegetables are grown commercially near Oamaru on a soil derived from basaltic ash.

Almost frost-free areas favoured for producers of early or “out of season” crops include Pukekohe Hill; the Gisborne district; Bay View, near Napier; the hill slopes near Nelson; the Port Hills, near Christchurch; and Otago Harbour district. Early potatoes are also grown at Outram, on the Taieri Plains. Northern districts have a longer production season than southern districts. Two (and often three) crops a year are grown on the same ground in the north; at Ohakune, and in the south, one or two crops a year is usual.