Sunflowers (Helianthus annuus) produce seeds encased in dark shells or hulls. The most familiar seeds are teardrop shaped and black-and-white striped. Sunflower seeds have a variety of uses--bird food mixes, oil and snack foods. Today, polyunsaturated sunflower oil is one of the healthiest cooking oil used. Gardeners enjoy growing sunflowers because of their hardiness and beauty.
According to the National Sunflower Association, sunflowers have been part of our diet for more than 5,000 years. Native Americans made flour for cakes and breads from the seeds, used the natural oil and crushed the flowers to make purple dye and body paint. In 1500, Spanish explorers took seeds back to Spain and introduced them to the rest of Europe. The seeds made it back to the United States in the early 1900s, and today many enjoy eating them.
Sunflower seeds are a healthy snack that supplies vitamin E, magnesium and selenium. Vitamin E helps control inflammation in the body, which is helpful for immune disorder sufferers like those with arthritis. Magnesium from kernels helps lower high blood pressure and reduces the risk of a heart attack or stroke. According to the George Mateljan Foundation for the World's Healthiest Foods (a health non-profit), ongoing studies support selenium as a cancer protector.
Ideally, sunflowers are planted an inch to 1 ½ inches deep and will sprout in four to five days. If planted deeper or in cooler soil it will take a little longer for seedlings to emerge. Planting can begin once the soil temperature is above 50 degrees Farenheit, usually from April through July. Avoid planting in wet soil and narrow rows for easier maintenance. Once above ground, sunflowers grow quickly; two months to maturity is typical.
The average sunflower is finished growing when it is 6 feet tall and the blooms begin to face downward. The seeds are ready to be harvested when the back of the flower head turns yellowish-brown. To harvest, cut off the head and the top 6 inches of stalk. Hang it upside down in a well-ventilated shed or garage to dry out. Once the flowers are completely dry you can pick up two flower heads and simply rub them together to extract the seeds or use your hands to rub the seeds out.
Sunflower varieties are categorized by size. The giant variety can reach a height of more than 10 feet--a flower grown in the Netherlands holds the Guinness world record at 25 feet, 5.4 inches.
Regular sunflowers can grow up to 10 feet, and miniatures stand 2-to-4 feet high. Minis are popular in Asia and are used as border flowers in the U.S.
Varieties are further divided depending on the number of heads the flower has. Large-headed varieties could have one big head or a few smaller ones on lower branches. Every type of sunflower has edible seeds that are enjoyed by birds, wildlife--and people.