Sow the seed into finely raked, moist, warm, weed free soil where the plants are to flower, 13mm (½") deep April/May (germination 10-21 days). Remove the growing tips of plants when 3-4 pairs of leaves have developed to promote more flowers. For early flowering, sow January/March in a greenhouse or indoors 3 seeds per 10cm (4") pot, 13mm (½") deep and plant out in May/June.