Hardy annual seed may be sown outdoors in early spring, whilst half-hardy annuals may be grown indoors in a heated propagator in the greenhouse or on a windowsill indoors. In mid-spring, prick out half-hardy annual seedlings or pot them up in containers, and then plant them out into prepared ground in late spring, once all danger of frost has passed. At this point, hardy biennial seed may also be sown outdoors.

Make sure that growing plants are watered regularly. Supports should be provided for tall plants or climbers. In late spring, pinch out (or 'stop') any plants that need to be encouraged to produce sideshoots and develop a bushy habit.