How to Care for Sunflowers
Sunflowers are usually problem-free. Plant early enough so that autumn frosts do not cut your sunflowers’ life cycle short. Too much rainfall before and after germination can cause the seeds to rot or bring on downy mildew. Be sure to seed after the rainy season to avoid this.
If you would like to harvest the seeds to either replant next year, wait until the end of the bloom cycle. Sunflowers blooms often last 30-45 days. Toward the end of this period, the green back of the flower head will begin to turn yellow and will usually droop at this time. You will also see the seeds swelling on the face of the sunflower. Cover the flowers with paper bags to protect them from birds. Cut off the flower heads and leave inside the brown paper bag. Store this bag in a well-ventilated place like a garage until fully dry. Rub along the seeds with the palm of your hand and the seeds should fall right out into your bag, or work over a cookie sheet. Store seeds in a cool, dry environment until you are ready to reseed next year.