Sow indoors:Â January to March, in trays of seed compost. Sow thinly, cover with 0.5cm of fine soil. Firm gently and keep moist. Place in a cold frame or unheated greenhouse. Seedlings appear in 14-35 days. When large enough, transplant singly to 7.5cm pots. Gradually acclimatise to outside conditions. Transplant 30cm apart in flowering position from September to October. Keep moist and weed free.