For early flowers, sow under glass in early spring. Fill a seed tray or pot with good quality compost and space the seeds at 2.5cm intervals and just cover with a sprinkling of compost. Water moderately and when the seedlings are large enough to handle pot on and harden off before planting outside. Alternatively sow thinly outside in a sunny bed after all risk of frost has passed. Thin to 25cm as they grow on. Sowing several batches with a couple of weeks in between each will ensure the flowering period stretches from early summer to the first frosts.