Sow on the surface of a good seed compost, and cover with a light sprinkling of compost or vermiculite. Place in a propagator at a temperature of 21-24?C (70-75?F) or seal the seed tray inside a polythene bag until after germination which takes 10-21 days.
When seedlings are large enough to handle, transplant into 7.5cm (3in) pots and grow on in cooler conditions. When plants are well grown and all risk of frost has passed, gradually acclimatise them to outdoor conditions for 10-21 days with shade from direct sun before planting them outdoors in their final positions.