F1 Hybrid Pollenless Sunflower Sunbright is the gold standard for sunflowers and very popular with growers and consumers due to its great shipping quality and bright golden petals. Being pollenless, Sunbright is excellent for cut flower purposes. F1 hybrid Sunbright is very uniform and vigorous in growth even under low temperature and short day conditions. Sunbright is an economical and profitable series.

Site Selection: Sunflower Sunbright grows well in any type of soil. Choose a sunny site with good drainage.
Soil Preparation: Sunflowers do best planted in relatively poor soil. Optimum pH range is 5.5 to 6.5. Soil that is too rich (EC over 0.7 mmhos 2:1 slurry) will cause the plants to grow too tall. Excessive Nitrogen; especially in the summer, will cause plants to grow too vigorously with abnormal flower shapes.
Seed Sowing: Sow seeds directly into beds and lightly cover with soil. Water the seed beds thoroughly and maintain 75 °F/24 °C air temperature, with a minimum soil temperature of 50 °F/10 °C. Seeds germinate in about 10 days. 7 to 10 days after seedlings emerge, thin out leaving only the strongest and most sturdy seedlings. A final spacing of 4 x 5 inches/10 x 12 cm is ideal. Dense growing will help to reduce the amount of side branching and yield a flower size of 5 inches/12 cm.
Temperature: After thinning, maintain a minimum air temperature between of 50 °F/11 °C during the night, and a maximum of 75 °F/ 25 °C. during the day.
Fertilizer: Sunflowers require little or no fertilizer to produce flower stems of high quality. Ideal E.C. level is 0.7 mmhos (2:1 slurry). Also, water the plants only moderately to avoid overgrowth and soft plants. Exercise extra care not to overfeed plants.
Note: Excessive application of Nitrogen fertilizer may result in overgrowth of plants, especially when grown as a summer crop.

Timing: Flowering time will be about 70-80 days in the summer* and 50-60 days in the winter and is related to day length and temperature. During short days, plants will flower more quickly with smaller discs on shorter stems. Under long day conditions, plants will flower later with larger discs and taller stems.
*Note: In Coastal California the cool night temperature will offset the long photoperiod resulting in earlier flowering.

Insects: Aphids, Lygus bugs and Whiteflies are the principal pests. Spray as needed.
Harvesting: Cut stems when the flowers are 1/4 open with the petals perpendicular to the center disc. To ensure the longest vase life, cut the stems at the proper stage. Late harvesting will result in reduced vase life.