Sunflowers
Planting, Growing, and Harvesting Sunflowers
You’ll find everything you need to know to plant and grow sunflowers in the accompanying table’s tabs:
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- How many sunflowers to plant
- Growing conditions for sunflowers
- When to plant sunflowers
- How to plant sunflowers
- Watering, fertilizing, and pruning sunflowers
- Companion plantings for sunflowers
- How to harvest, store, and use sunflowers
Growing Sunflowers
Sunflowers are prolific seed-bearing, warm-season annuals of the many-species Helianthus family, and relatives of Jerusalem artichokes [see: Jerusalem Artichokes or Sunchokes].
An ornamental plant, usually 5–12 ft. (1.5–3.7 m) tall, though dwarf cultivars of small stature are available, bear broad, toothed leaves and golden yellow, many-rayed, composite flowers, 4–18 in. (10–45 cm) wide with a pithy, central bed containing up to several hundred tasty seed.
Sunflowers attract pollinating bees and seed-eating wild birds, create borders, and beautify vegetable gardens.
Sunflower Plant and Care Guide
How Much to Plant
Allow 2–4 plants per household member; large-flowered cultivars yield 1–2 lbs. (450–900 g) of dried seed per plant.
How to Plant
Seed germinates in 10-14 days.
All Climates: Plant seed or transplant seedlings in full sun in spring when soil warms to 65–85°F (18–29°C).
Sow seed 1/2 in. (12 mm) deep, 8–12 in. (20–30 cm) apart, thinning to 18 in. (45 cm) apart, in rows 30–36 in. (75–90 cm) apart, or broadcast over an area and thin to 18 in. (45 cm) apart, installing stakes at time of planting in sites exposed to strong wind.
Best Conditions for Growth
60–105°F (16–41°C). Best in warm-summer climates.
Soil Type and Fertility
Damp, well-drained soil. Fertility: Rich. 5.8–6.2 pH. Prepare soil at least 18 in. (45 cm) deep.
Proper Care
Easy. Keep evenly damp; allow soil surface to dry between waterings. Fertilize monthly with acidic 5–10–10 formula or supplement with garden sulfur. Cultivate. Pest and disease resistant. Staggered rows of sunflowers provide shade, windbreaks for other plants.
Pairing Recommendations
Beans, cucumbers, peas, Malabar spinach; use sunflowers as living stakes for pole and vining plants.
Maturity, Picking and Gathering
70–80 days. Harvest heads with mature seed loosely held in flower heads when plants’ stalks and leaves dry, cutting stalks 1 ft. (30 cm) below the flower and hanging heads upside down in a warm, sheltered, and dry spot for 4–6 weeks to completely dry the seed.
How to Store and Preserve
Remove seed from heads by shaking over a clean tarp. Fresh, stored a cool, dry spot, for 6 months; roasted, sealed in airtight bags, and frozen, 1 year. To roast seed, spread on a cookie sheet, bake at 250°F (120°C) for about 1 hour. Raw or roasted seed will also feed birds throughout the winter.