Cauliflower need a rich, well drained but moisture-retentive soil, with a high humus content to provide better aeration and water penetration and with medium nitrogen levels. The soil should have been dug deep before planting the cauliflowers. When digging the soil work some organic compost or manure into the soil.
Success with cauliflowers depends on sowing the correct cultivar at the appropriate time. The cultivars are classified by the main season of use: winter, summer and autumn, although these groups overlap. Winter cultivars should be sown in late spring, plant out in summer and harvest in winter or early spring, depending if you are in a frost-free area or not. Summer cultivars should be sown in autumn or under glass in early spring, plant out in spring and harvest in early to mid summer. Autumn cultivars should be sown in mid to late spring, plant out in early summer and harvest in late summer to late autumn.
Sow cauliflowers in seed trays, modules or in a seedbed for transplanting later in small pots. Seeds germinate best at a temperature of about 21 Celsius degrees (70 F). Put the pots into a well-ventilated frame or under cloches. About 6 weeks after sowing the seedlings should be ready to harden off. Harden the seedlings off a week before planting out by gradually increasing the amount of time the plants are left outside and the amount of sun the plants receive. For a continuous supply of cauliflowers make successive sowings. Plant out the seedlings at about 60-70 cm apart. Water regularly because it is vital not to let the soil dry out as lack of water can lead to the production of small heads.
Start to harvest cauliflowers before they reach their full size, about 16 weeks from sowing for summer/autumn cultivars and 40 weeks for winter ones. Mini-cauliflowers mature about 15 weeks after sowing. Cut the stalk with a sharp knife but be sure to leave a number of leaves that surround the head to protect it. You can store cauliflowers for up to 3 weeks by hanging them upside down and mist-spraying with water every day.