Sow from February to May at 15°C (59°F) on the surface of a good free draining, damp seed compost. Do not cover seed. Place in a propagator or seal container inside a polythene bag until after germination which usually takes 10-30 days. Do not exclude light, as this helps germination.
Transplant seedlings, when large enough to handle, into 7.5cm (3in) pots. Gradually acclimatise to outdoor conditions and then plant out 30cm (12in) apart.