Under glass, sow seeds 2mm deep in a good quality seed compost and keep moist (but not wet) until they germinate. Thin out when they are large enough to handle and pot on. Gradually harden off before planting out after all risk of frost has passed. Alternatively, sow later in the year directly into a well-prepared bed. Seeds sown in autumn have a better chance of producing flowers in their first summer, while others usually won't flower until the following year.