Research data from North Dakota State University indicate root penetration and water use to a depth of 6 feet is similar for normal height and semidwarf sunflower. Beyond 6 feet, root penetration of the semidwarf may not be as great as that of taller plant types. Some sunflower breeders have observed that short-stature plants have demonstrated limitations in head size and ability of the plant to fill the center of the head. Also, slower seedling emergence has been reported for semidwarfs. Production Practices Seed Quality High quality, uniform seed with high germination, known hybrid varietal purity, and freedom from weed seeds and disease should be selected to reduce production risks.
Seed is sold on a bag weight basis or by seed count.
Seed size designations are fairly uniform across companies. Most seed is now treated with a fungicide and insecticide to protect the germinating seedling. Production performance on high-stress soils such as those affected by droughtiness, salinity, or wetness is not exceptional but compares favorably with other commercial crops commonly grown. Soil Fertility Sunflower, like other green plants, requires at least 16 elements for growth. Some of these, such as oxygen, hydrogen and carbon, are obtained from water and the air.