Growing Sunflowers Organically
Native to Central America, sunflowers (Helianthus annuus) are not only a distinctive annual flower to use in brightening up the garden but also a useful, edible plant. They are easy to grow and their huge blooms give great satisfaction once they start to flower. They are a great plant for children to grow. The most distinctive feature of sunflowers is their large, often singular, yellow flower heads. It's not hard to work out why this flower was given its common name when viewing one of these gigantic yellow flowers against a bright blue sky. The flower head of the sunflower, like other members of the Asteraceae family, is actually an inflorescence of one to two thousand smaller flowers known as florets. The outer flowers (what we know as petals) are called ray florets, these are sterile and don't produce any seed. The inner flowers are called disc florets and it is these, that after pollination, form the edible seeds we know and love (as do the birds). The disc florets are arranged into a unique interconnected spiraling pattern which maximizes the number of florets that can fit within the space of the flowerhead. A common misconception about sunflowers is that their flowers track the sun (a phenomena known as heliotropism), in fact the flowers mostly face East and do not change direction during the day. The leaves and buds of young plants do however have the ability to track with the sun.
Sunflower seeds can be eaten raw or roasted, with or without salt. Oil is extracted from the seeds commercially to make sunflower cooking oil. Sunflower seed can also be sprouted and eaten raw. The young flower heads can be steamed and served like globe artichokes. Teas and poultices made from the dried leaves can be used medicinally for a range of ailments, visit the plants for a future website for more details on medicinal uses. Sunflowers are bio-accumulators and have been used to remove toxins including arsenic, lead and uranium from the soil. After the Chernobyl nuclear power-plant disaster they were used to remove contaminants from a nearby pond. They also attract beneficial insect pollinators to the garden and are a repellent to pest armyworms.
Sunflowers do best in full sun, with non-dwarf varieties growing up to 3m tall. They can cope with a variety of soils but do best in well-mulched, well-drained, heavily composted soils. Seed can be sown directly and should be spaced 40cm (16 inches) apart and planted 2.5 cm (1 inch) deep. The roots of sunflowers secret a chemical which can inhibit the growth of nearby plants so be careful to space them out appropriately. Sunflowers are not self-fertile so you'll need at least two to produce any seeds. The plant will self-sow if growing conditons are good. Some larger cultivars may require staking to prevent their stems from collapsing under the weight of their flowers, especially if there is a bit of wind about.
The seed from all sunflower varieties is edible, although some cultivars will have bigger and tastier seeds than others. The eating quality of sunflowers can often be determined by looking at the colour of the seed husk. Generally, totally black sunflower seeds have a higher oil content and are used for extracting oil or as bird feed, whereas black and white stripped varieties are better for eating.
The following cultivars are good for eating and worth looking out for, although this list is by no means comphrensive so if you know of a good variety let everyone know by posting in the comments below: