Sow early spring to early summer outdoors where they are to flower. Prepare the ground well and rake to a fine tilth before sowing. Sow 12mm (0.5in) deep in rows 45cm (18in) apart.For really giant sunflowers, sow them indoors in late winter/early spring, individually in 7.5cm (3in) pots at a temperature of 15-18C (60-65F). Grow on in good light conditions, harden off and plant out when all risk of frost has passed.
They prefer a sunny open site but will grow in most sites and soils.