Sow indoors for surest results, February-April, 0.5cm (¼”) deep, in trays of compost. Water well and place in a warm position. A temperature of 15-20°C (60-68°F) is ideal. Keep moist. Seedlings usually appear in 14-21 days. Transplant them, 5cm (2″) apart, to other trays when large enough to handle. Grow on in cooler, but not cold conditions. Gradually accustom young plants to outside conditions (avoid frosts), before planting out into well-drained soil, May-June, 20cm (8″) apart, when frosts are over. Or, sow outdoors for ease, April-May, where they are to flower, 1.5cm (½”) deep, directly into finely-prepared, well-drained soil, which has already been watered. Thin seedlings as required. Water well until plants are established. Flowers: June to October.