Sow January-March or September-November. Sow on the surface of free-draining, damp compost, covering lightly with compost. Place in a heated propagator, or on a sunny windowsill. Do not exclude light, as this helps germination. Pot up into small containers when big enough to handle. Plant out after last frost if spring sow, overwinter autumn sown plants in a coldframe or cold greenhouse ready to plant in spring, 30cm (12") apart.