The brassica crop comprises broccoli, brussels sprouts, cabbage, cauliflower, swedes, turnips, radish, broccoflower and Asian greens. In 2007 there were 290 growers of brassicas. They cultivated 3,500 hectares and produced some 82,000 tonnes of produce. The three main crops are cabbage, cauliflower and broccoli. Major regions of production are Auckland, Manawatū and Canterbury. Almost all production is consumed on the domestic market. A small amount of cabbage is exported to Hong Kong, Malaysia and Thailand.
The leafy crops include lettuce, silverbeet (Swiss chard), spinach, mesclun mixes and watercress. In 2007 there were 315 growers of outdoor lettuce on 1,200 hectares, and 122 silverbeet and spinach growers with 400 hectares under cultivation. Main regions of production are Auckland, Manawatū and Canterbury. The majority of leafy crops are consumed domestically, with a small volume of lettuce exported to Hong Kong. Most of the lettuces grown outdoors in New Zealand are iceberg lettuces which have firm, tightly packed heads.
Carrots and parsnips
Carrots need deep sandy loam soils and relatively cool conditions for good growth. A spring crop is planted at Pukekohe during autumn and winter (from March to September) and the main winter crop is planted at Ōhakune and South Island locations between September and December. In 2007 some 65,000 tonnes of carrots were produced from 1,800 hectares. Two-thirds of the crop was consumed in New Zealand, the rest was exported. Since the 1990s an export market has developed to Japan, Thailand and the Pacific. Parsnips are grown in Pukekohe and Ōhakune for the domestic market.
Kūmara – sweet potato
Sweet potatoes (Ipomaea batatas) are known as kūmara (their Māori name) in New Zealand. New Zealand’s crop is grown on the fertile plains of the Wairoa River near Dargaville, in Northland. Kūmara are planted in October and harvested 126 days later in mid-January. Good crop yields are around 15 tonnes per hectare. In 2007, 90 growers produced around 18,000 tonnes, which was worth NZ$34 million on the domestic market. Three varieties are grown. The most popular is Owairaka Red – a reddish- purple-skinned variety with creamy yellow flesh. The others are Beauregard, an orange-skinned variety, and Toka Toka Gold with a yellow skin.
Most of the corn grown in New Zealand is grown as stockfeed and is better known as maize. The types of corn grown in New Zealand for human consumption are varieties of sweetcorn. Sweetcorn is a natural mutant form of field maize that does not convert all the sugar in its kernels into starch. Annual sweetcorn production in New Zealand averages about 97,000 tonnes from a crop area of around 6,400 hectares. There are approximately 280 growers. Since 2000 the volume of sweetcorn grown for freezing and the fresh market has increased, mainly due to the introduction of supersweet varieties. Major production areas are Gisborne, Hawke’s Bay, Marlborough and Canterbury.
In New Zealand it is illegal to grow genetically engineered (GE) crops commercially. In 2002 a controversy arose about whether sweetcorn had been grown from GE seed imported from the US. Although it was never established whether GE seeds had been planted, the event became politically damaging to the government – it was revealed that ministers knew GE seed might have been planted. The media labelled the incident ‘Corngate’.
Supersweet corn originated as a chance mutation of sweetcorn in 1962. It has a higher sugar content in its kernels than normal sweetcorn. Supersweet corn stores well and does not require extra sugar to be added when it is canned.
Asparagus was a popular crop with growers in the 1990s, but following outbreaks of Phytophthora – a soil-borne rot that severely affects asparagus – the number of growers and amount of land in production declined. In 2006 there were 126 asparagus growers, who produced 2,500 tonnes from 710 hectares of land. About half the crop is consumed by the local market, the rest is exported or processed. Japan is the major overseas market for fresh product. Waikato, the south-west North Island, and Hawke's Bay are the main producing areas.