A warm kitchen windowsill is all you need for starting these seeds. Sow thinly on the surface of a small tray of pre-watered compost. Place in a warm, light position. A temperature of 15-20°C (60-68°F) is ideal. Keep the compost moist. The tray can be covered with clingfilm to preserve humidity but removed when seedlings appear, usually in 14-21 days. Transplant them, in tiny clumps, 5 cm (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, May-June, 15cm (6") apart, into well-drained soil, when frosts are over. Sow indoors between January and April for flowers during June and October.