How to grow Sunflower

Helianthus annuus · common sunflower

Fast-growing warm-season annual, 0.6–3 m tall, with big yellow flower heads that follow the sun; easy from seed. It draws pollinators and beneficial insects, and birds eat the seeds.

Quick facts

Type	Flower
Family	Asteraceae
Light	Full sun
Soil pH	6–6.8
Frost	does not tolerate frost
Soil for sowing	from 16 °C
Germination	7 days
Where it grows	Greenhouse, Open ground

When to plant

Sow straight into the bed after your last spring frost, once the soil has warmed.

In an unheated greenhouse everything moves about three weeks earlier.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Growth	every 3 days	—	balanced (NPK), at the start of the stage; nitrogen, 42 days into the stage
Flowering	every 3 days	—	—

Open ground

Stage	Watering	Temperature	Feeding
Growth	every 3 days	—	balanced (NPK), at the start of the stage; nitrogen, 42 days into the stage
Flowering	every 3 days	—	—

Growing notes

Light

Needs full sun.

Soil

Grows in almost any soil that is not waterlogged; best at pH 6.0–6.8. It tolerates poor and dry soil and stands drought once established.

Care

Sow outdoors several weeks after the last frost, once the soil is at least 16 °C, 2.5–5 cm deep (deeper in sandy soil), and thin the seedlings to 30–38 cm apart. Sow every 1–2 weeks for flowers all summer. Water lightly for the first 7–10 days, then a couple of times a week if it does not rain. Work in a balanced fertiliser before sowing and side-dress with nitrogen later on. Plant tall varieties out of the wind and stake them if needed. Watch for aphids, caterpillars, stink bugs, powdery and downy mildew, rust, and deer.

Pests and diseases of Sunflower

Sources

Figures checked against these sources.