How to grow sunflower in Australia
Sunflowers are the easiest large flowering plant you'll grow — direct-sow a seed in warm soil and within 60–90 days you have a 1–3m tall plant with a flower head the size of a dinner plate. They're useful as well as decorative: the seeds are edible (and birds love them), the tall plants provide afternoon shade for cool-season vegetables nearby, and the flower heads track the sun across the sky in young plants — a remarkable bit of botany you can watch happening over the course of a day.
When to plant
Sunflowers need warm soil and a long warm season. Frost-sensitive at both ends.
April to August in the dry season.
September to February.
September to January.
October to December. Plant after Melbourne Cup weekend.
November to December. Short window — choose faster-maturing varieties.
August to October.
Your planting calendar
Showing Melbourne 3000
Loading climate data…
Open the full planting calendar →How to plant
Sunflowers are direct-sown — they don't transplant well due to the long taproot.
Spacing: 30–60cm between plants depending on variety. Giant types (Russian Mammoth) need wider spacing; smaller types can be planted closer.
Depth: 2–3cm deep.
Soil: Average garden soil. Sunflowers tolerate poor soil but produce larger flowers in good conditions. Slightly alkaline pH preferred.
Support: Tall varieties (over 1.5m) may need staking in exposed positions to prevent blowing over.
Succession planting: For continuous flowering, sow a small batch every 3–4 weeks through the suitable season.
Pots, raised beds, or in-ground?
Sunflowers vary enormously by variety — from 30cm dwarf types in pots to 3m+ giants only suitable for open ground.
In-ground is the standard for large varieties. The deep taproot needs unrestricted soil.
Raised beds work well — particularly for medium-height varieties (1–1.5m).
Pots suit only dwarf varieties. Sunspot, Big Smile, and similar compact types (30–60cm) work in 25cm+ pots. Standard sunflowers need ground or large planters.
Sunlight & water
Full sun — 6 to 8 hours daily.
Water deeply but infrequently. Sunflowers are reasonably drought-tolerant once established.
When and how to harvest
Sunflower heads are ready when the back of the flower turns from green to yellow-brown and the seeds begin to plump. Birds will start to eat the seeds at this point — cover heads with mesh bags if you want to harvest seeds yourself.
Cut heads with 30cm of stem attached and hang upside down in a dry ventilated spot for 1–2 weeks to fully dry. Rub the seeds out by hand once they're loose.
Edible varieties (most are) produce striped or grey seeds that can be eaten raw or roasted. Birds love sunflower seeds — leaving heads on the plant is a useful way to feed local wildlife.
Common problems
Birds eating seed heads before harvest. Cover with mesh bags if you want the seeds.
Blowing over in wind — stake tall varieties in exposed positions.
Slugs and snails on young seedlings. Protect with beer traps or copper tape.
Powdery mildew on leaves late in the season. Cosmetic; doesn't significantly affect seed development.
Companion planting
Plant near: Cucumber, pumpkin (sunflowers provide structure and shade), beans (can use the stalks as climbing support), corn.
Keep away from: Potatoes (some allelopathic effects reported).
Australian varieties
Russian Mammoth — Giant variety reaching 2–3m+ tall with flower heads up to 30cm across. Heritage variety. Productive seed crop.
Yellow Empress — Standard 1.5–2m variety with classic yellow flowers. Reliable across all climates.
Sunspot — Dwarf variety, 30–45cm tall, large flower heads relative to plant size. Excellent for pots.
Teddy Bear — Compact dwarf (45cm) with fluffy double flowers. Decorative.
Autumn Beauty — Multi-coloured variety with red, orange, yellow, and mahogany flowers. Medium height (1.5m).
Lemon Queen — Pale yellow flowers with multiple heads per plant. Continuous blooming.