FARMING, ARABLE - VEGETABLE INDUSTRY
Before the Second World War most vegetables for market were grown close to cities and towns to take advantage of shorter and cheaper cartage for perishable crops. Many growers carted their own produce to market. Potatoes and onions, better travellers and storers, could be grown further afield. Main-crop potatoes were grown mainly by farmers in mixed cropping districts; early potatoes were usually associated with other vegetable production in districts that were little subject to frost. There were few vegetables grown for canning. Since the Second World War there have been big changes in the vegetable industry: a great increase in crops for processing and loss of more than 3,000 acres of former market-garden land close to cities. Such areas are mainly at Avondale and Panmure, near Auckland, in the Hutt Valley, near Wellington, and at Marshland, Burwood, Papanui, and the Port Hills, around Christchurch. Except for main-crop potatoes and, perhaps, onions, most vegetables for market are grown intensively or semi-intensively on market gardens of 5 to 50 acres, though there are a few of between 100 and 200 acres. Those below 5 acres, some of which are part-time workings, are often associated with glasshouses or with the growing of specialist crops such as lettuce and celery.
Crop rotation is important in intensive cultivation and it is usual for several kinds of vegetables to be grown. Specialist growers, especially on smaller areas, enrich their soil with heavy applications of organic matter. Some green cropping is done on many market gardens. On some, vegetable production is associated with livestock farming, and the vegetable crops are rotated around the farm. In the Ohakune district particularly, vegetables are grown for one or two years in rotation with pasture. The light volcanic soil in this area quickly loses structure and is liable to severe wind erosion if it is cropped for more than one or two years at a time. Peas for processing are often grown by farmers who use the crop to provide a cash return in the course of ploughing up old pasture and resowing with new grass.