Sow seed on the surface of good, free-draining, seed compost. Cover with a very fine sprinkling of compost or vermiculite. Place container in a propagator or seal container inside a polythene bag and place at a temperature of 20-25C (68-77F) until after germination which usually takes 7-21 days. Do not exclude light, as this helps germination.
Transplant seedlings when large enough to handle into trays or 7.5cm (3in) pots. Gradually acclimatise plants to cooler conditions for a few weeks before planting out after all risk of frost, 30cm (12in) apart.