Tall Sunflowers - Key Growing Information
DAYS TO GERMINATION: 7-14 days at 70-75°F (21-24°C).
SOWING: Direct seed (recommended) — After the last frost, sow in groups of 2-3 seeds, 1/2" deep. Thin to one plant when true leaves appear. Transplant — Sow in final plug flats
3-4 weeks prior to planting out. Sunflowers dislike root disturbance and do not transplant well. Transplants should be held indoors for no more than 4 weeks prior to planting out. Provide sun and good air movement.
LIGHT PREFERENCE: Sun.
SOIL REQUIREMENTS: Light, well-drained soil. Excessive nitrogen may cause plants to grow too vigorously with abnormal flower shapes.
PLANT SPACING: 4-24". Single-stem varieties space 4-6" apart. Branching varieties space 18-24" apart.
HARDINESS ZONES: Annual.
HARVEST: Fresh — Flowers can be harvested tight when color first begins to show, or when the flowers are just beginning to open, depending on your market. Dried — Flowers are completely open. Hang or use silica gel.
USES: Excellent cut flower or for gardens.
NOTE: For early and late season production, select varieties that are day-length neutral or are noted as suitable for flowering under short days. See our Single-Stem Sunflower Commercial Production guide #8283 for more information.
SCIENTIFIC NAME: Helianthus annuus