Choose an open, sunny site and sow the seed thinly direct outside into finely raked, moist, warm, weed-free soil where the plants are to flower 6mm (¼") deep. Germination takes 10-21 days. Thin in stages to a final spacing of 23cm (9") apart. Alternatively, sow in pots or trays indoors at approximately 15-20°C (60-68°F) in a good quality, finely sieved, moist compost. Transplant seedlings spacing them 5cm (2") apart in trays and grow on. Plant out after first acclimatising to outside conditions.