Brassica oleracea, Botrytis Group
Family: Brassicaceae

Although a biennial, cauliflower is mainly grown as an annual. It is easiest to grow in cool climates, being more difficult in regions with hot dry summers or very cold winters. It is the edible, immature flower head of this popular vegetable that we enjoy eating as a cooked vegetable with white sauce, or in salads. The condensed flowers and flower stems form the swollen head or curd. There are varieties of cauliflower suitable for harvesting in summer, autumn and winter.

Varieties

These vary according to location. Good seed catalogues will list a range of summer, autumn and winter cauliflowers.

Cultivation

Cauliflowers do best in a wellmanured, deeply dug, loamy soil, with a pH of 6-7. They also need good drainage and plenty of sun. Prepare the soil about three weeks before planting the seedlings by adding old manure or compost and about 100 g (3 oz) of complete fertilizer per square metre (square yard). Keep weeds down and water liberally. The seeds germinated in pots or trays should be transplanted when about 10-15 cm (4-6 in) high. Space smaller varieties about 50 cm (20 in) apart within rows and between rows, and the larger at 60-75 cm (24-30 in). Sowings must be made at the correct time. Varieties for early summer cutting are sown in autumn in a garden frame or in midwinter in a heated greenhouse, and are planted out in mid-spring. Varieties for harvesting in summer and autumn are sown in spring in a greenhouse or in late spring outdoors. They are transplanted in early summer. Winter cauliflowers are sown outdoors in early summer and transplanted in midsummer. The ideal temperature for germination is 21°C (70°F). They need a generous soaking of water once a week, to encourage the roots to move downwards in the soil. Watch for attack by insect pests and diseases. In addition, a deficiency of the trace element molybdenum sometimes occurs and this can cause a condition called 'whiptail', which prevents flower set. Adding lime to the soil before planting will reduce acidity which prevents molybdenum being released to the plant. As a preventative measure where soils are very acid, spray the plants with sodium molybdenate at the rate of 7 grams ('A ounce) to 11 litres (20 pints) of water. As the curds mature, tie the outer leaves over them to prevent discolouration and to keep them tender. Harvest the heads before they open up, while still firm.

Climate

Zone 8.