Sow indoors March to April. Sow thinly 0.5cm deep into trays of compost. Water well and place in warm, light position, away from cold draughts and out of intense, direct sunlight. Keep the compost just moist and be careful not to overwater, the compost should almost dry out before it is watered again. Seedlings should start to appear in approximately 7-21 days. Carefully transplant the seedlings to individual pots when they are large enough to handle and keep moist. In late May or early June, acclimatise plants to outside conditions. Place plants outside in a sheltered spot during the day and bring them inside again at night when temperature fall. Do this for a week or two, until the plants have hardened off. Then transplant to a sunny growing position 45cm apart. If space is limited plant 25cm apart for mini-heads. Plant seedlings deep, right up to the first set of leaves and be sure to firm the young plants in well to prevent the plants from rocking in the wind, which can damage their delicate roots. Keep the soil moist and remove any weeds as they appear.