How to grow sunflower
Overview
Sunflower (Helianthus annuus) is a fast-growing annual herb grown for edible seeds, cut flowers, and bird attraction. It thrives in warm weather and needs full sun to produce large, healthy flower heads.
Varieties
- Giant Single — Classic tall variety (2–3 m) with large single head, excellent for seed production.
- Sunray — Dwarf branching type (60 cm) ideal for pots and cut flowers, multi-headed.
- Lemon Queen — Pale yellow, pollen-rich variety (1.8 m) that attracts bees and birds.
- Mammoth Russian — Very large seed head (30 cm), heavy yields, good for oil and roasting.
Soil Preparation
Sunflowers prefer well-drained, loamy soil with pH 6.0–7.5. Enrich with compost or well-rotted manure before planting. Avoid waterlogged or heavy clay soils.
Growing Guide
Sow seeds directly 2–3 cm deep, 30–45 cm apart in rows 60 cm apart, or thin to 45 cm spacing after emergence. Choose a sheltered, open site with well-drained soil. Water deeply at planting, then weekly until established. Stake tall varieties (over 1.5 m) in exposed gardens to prevent wind damage.
Sowing
Sow seeds 2–3 cm deep, 15–20 cm apart, thinning to 45 cm after emergence. Germinates in 7–14 days at 18–25°C. Direct sow is best; transplant only if using biodegradable pots to avoid root disturbance.
Care
Feed every 2–3 weeks with a balanced liquid fertiliser (e.g., 10-10-10) during active growth. Remove spent flower heads to extend blooming. No pruning required; stake tall varieties if needed.
Companion Planting
Plant near corn, squash, and cucumbers to share trellis support and attract pollinators. Avoid near potatoes or beans as sunflowers may compete for nutrients and space.
Common Pests & Risks
Aphids, caterpillars (especially cutworms), and birds (parrots, finches) are common. Control aphids with a strong water spray or neem oil; protect seed heads with netting or paper bags as they ripen.
Harvesting
Harvest seed heads when the back of the head turns yellow-brown and the seeds are plump and firm. Cut the stem 30 cm below the head and hang in a dry, airy place for 2–3 weeks before removing seeds.
In the Kitchen
Harvest seeds when dry and store in airtight containers. Roast at 160°C for 15–20 minutes for a nutty snack. Use raw in salads or grind for sunflower seed butter.
Troubleshooting
Yellow leaves: overwatering or nitrogen deficiency. Reduce water and feed with liquid seaweed. Brown edges: sun scald or heat stress. Provide afternoon shade in hot climates. Stunted growth: poor soil or root competition. Ensure 45 cm spacing and enrich soil. Drooping heads: wind damage or heavy rain. Stake early and tie loosely.