Chinese broccoli
Commercial production
Department of Primary Industries and Fisheries, Queensland.
- Figure 1. The flowering stems of Chinese broccoli are sold in bunches
Although Chinese broccoli is more closely related to the European cabbage than Chinese cabbage, it is still regarded as an Asian vegetable. Chinese broccoli (Brassica oleracea cv. group Chinese kale) is also referred to as gai lum, kailaan, white-flowering broccoli, Chinese kale or gai lan. Normally grown as an annual, this rather stout plant with grey-green waxy leaves grows to 45 cm when mature. Chinese broccoli is cultivated for its flower stems with the attached younger leaves. The flower stems are usually 2 cm in diameter and 15 to 20 cm long when harvested (Figure 1).
Climate and soil
Chinese broccoli is a cool season crop with some frost tolerance but may be grown all year round in both the tropics and temperate regions. The optimum temperatures for growth is 18 to 28°C but the lower temperatures are ideal to promote early flowering and are necessary for complete floral development. Optimum temperatures for germination are 25 to 30°C. When the plant is young, it is especially important that uniform conditions are favourable, that is, not too wet, dry, shady or windy. Heaviest yields are obtained from mid to late summer sowings that mature in late summer and autumn. In cool areas delay sowing until midsummer as earlier sowings may bolt prematurely.
Chinese broccoli grows on most soil types providing the soil is fertile, with good drainage and has a high level of organic matter. The soil pH is ideal between 6.0 and 7.0. Do not let the pH fall below 5.0.
Cultivation
Chinese broccoli can be directly sown at a depth of 0.6 cm allowing 8 to 12 cm between plants and with 2 to 4 rows per raised bed. Usually Chinese broccoli is sown at a density of 108,000 to 220,000 plants/ha and then thinned after 3 weeks of growth. Thinned plants can be sold as the first harvest. A high density slows down the maturation process and produces a more desirable product. Chinese broccoli can also be transplanted 3 to 4 weeks after sowing. However take care if using seedling trays as growth rates are often too fast, particularly in warm weather, causing early flowering and minimal vegetative production.
A base dressing of 500 kg/ha of an 8:11:10 or similar mix, followed by a side dressing of 125 kg/ha CaNO3 or equivalent at 4 weeks after emergence (or 3 weeks after transplanting) is commonly used. Dual Gold (metalochlor) can also be applied at 1.5 to 2 L/ha directly after transplanting to control a range of weeds. Chinese broccoli requires frequent light watering for optimum growth.
Pests and disease
Chinese broccoli is particularly susceptible to downy mildew, as well as white rust and Alternaria, all of which can be managed by registered fungicides. Aphids, green looper caterpillar, white butterfly caterpillar and diamondback moth are common pests of Chinese broccoli. Registered insecticides can help manage these pests.
Harvesting, storage and marketing
Chinese broccoli is generally harvested between 50 and 70 days after sowing. Young flowering stems are selected with compact florets and small leaves attached, and cut by hand at 15 to 20 cm length with a sharp knife. The white flower buds should be developed but not open. Chinese broccoli should be harvested frequently to prevent bolting and toughening, particularly in summer. About three cuts can be obtained from one stem, and the main stalk should be cut relatively short to enhance further growth. A liquid feed after harvest may benefit regrowth. The average yield in a season with two to three harvests is 6 to 11 tonnes per ha. However, yield depends on harvesting frequency and method.
Chinese broccoli is harvested in the early morning to minimise water stress. After gentle washing tie them into bunches of five to seven plants and secure them with rubber bands or string. The main stem should be 10 to 15 cm long and 1.5 to 2.0 cm wide at the base. Common postharvest defects include open or deteriorating flowers and yellowed or decayed leaves. Chinese broccoli stores for more than 21 days at 2 to 5ºC as long as the relative humidity is 90 to 95%. At 5 to10ºC the shelf-life is reduced to 7 to 14 days. Do not store with ethylene-producing produce as Chinese broccoli is ethylene-sensitive.
Additional information sources
- Recommended Reading: Larkcom, J. (1991) Oriental Vegetables. John Murray (Publishers) Ltd, London.
DPI&F information and services
- To access DPI&F's information and services, Queensland residents can contact the DPI&F Business Information Centre on 13 25 23 for the cost of a local call, from 8 am to 6 pm Monday to Friday (excluding public holidays). E-mail callweb@dpi.qld.gov.au. Non-Queensland residents phone (07) 3404 6999.
- Current national information on agricultural chemicals registered for use on all crops is available on the Infopest CD-ROM. Write to DPI&F, GPO Box 46, Brisbane, Qld 4001, E-mail infopest@dpi.qld.gov.au, visit the Infopest web page, or phone (07) 3239 3967 for further information.
- This Note is also published on the DPI&F's PrimeNotes CD-ROM.
- Other horticultural information is available on the Plant industries home page.
Industry links
- Industry links is a page of links to various sites of interest to horticultural growers.
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries, Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last updated 22 October 2007
