To grow giant sunflowers, sow them singly under glass into multipurpose compost from March-April and outdoors from April-June once all risk of frost has passed. Your flowers will appear between July and September. Sunflowers need lots of sunshine to thrive and a sheltered position helps to keep your top-heavy giants upright.
Sow: April to May
Harvest: September to October
Visit the GIY Veg directory for more growing details and tips.