Production of Chinese Cabbage in Norway

Abstract

Abstract Chinese cabbage is adapted to late season production, which allows a crop to be started at high temperatures and form the head in a long, cool autumn with short days. Chinese cabbage can utilize high temperatures for growth, but high temperatures delay head formation. High temperature also increases the risk of tipburn (calcium deficiency) and bacterial diseases. Following low temperatures at an early stage of growth, high temperatures even promote bolting. To reduce the risk of bolting, the plants are, in Norway, always raised at temperatures above 18-20 C. Very early in the spring, the temperature in the field is increased by using a plastic cover for 3-4 weeks. Crops planted out from 10-15 May until 10-20 June are often covered for 1-2 weeks with floating spunbonded materials. In the Oslo fjord area, Chinese cabbage can be harvested in the open from late May to early October. With respect to bolting, spring production is safer than early summer production. The explanation is that the temperature in May, normally low, restricts the elongation of the seed-stalk during head formation. Tipbum rarely occurs early in the season, due to a marked fluctuation in daylnight temperatures. The risk of tipbum is reduced by restricting the growth by limiting nitrogen. Bacterial soft rot is a serious problem in the production of Chinese cabbage. The disease occurs mostly in hot, humid weather. Chinese cabbage grown in the Oslo fjord area has to be stored from about 1 October. A physiological disorder, brown midribs, restricts the storage period to 3 months. Cultivars insensitive to the injury are not adapted to the Norwegian autumn. CA-storage of Chinese cabbage might improve the storing ability, but is not at present in practical use. KEYWORDS: BoltingBrassicastipburnsoft-rotstoring