The commercial sunflower is an annual broadleaf plant that grows 3 to 6 feet high. It has a strong taproot and a prolific lateral root spread. The leaves are phototropic and follow the sun s rays with a lag of 12 degreeds behind the sun s azimuth. Sunflowers require five to seven days from planting to emergence. 40 days to visible heads, another 26 days to the first anther, up to eight more days for all plants to bloom, then another 30 days to physiological maturity.
Sunflowers grow well in semi-arid regions of the world.
Seeds will germinate at 39 degrees F but soil temperatures of 46-50 degrees F are most satisfactory. 20 days before until 20 days after flowering. On fertile soils. Sunflowers do not adapt to poorly drained soils. During the first or second week in June.