When to plant Sunflower in Temperate Australia
Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.
Sunflowers are sown direct from August to December in temperate Australia, 8–12 mm deep, straight into their final position — the deep taproot means they establish far better unmoved than transplanted. Germination takes anywhere from 6 to 21 days depending on soil warmth, and flowers arrive 80–100 days after sowing. Spacing is your main creative decision: plant 20 cm apart for slender, small-headed stems that suit a vase, or up to 60 cm apart (rows 60–90 cm) for the towering single heads children measure themselves against. Sow a short row every few weeks for months of continuous colour.
Sowing calendar — temperate zone
Green months are your sowing window: August to December.
Growing notes
August sowings go in while frosts are still possible — the temperate last frost typically lands mid-October — but sunflower seedlings are hardy enough to take light frosts in their stride; the real cost of very early sowing is simply slow, reluctant germination in cold soil, at the long end of that 6–21 day range. October to December sowings leap out of warm ground within a week and often overtake earlier rows. Later sowings also flower into autumn, stretching the display.
Give them the most sun you possibly can, in any reasonable free-draining soil; for giant heads, enrich the bed with compost and water deeply through the stem-building phase. Heads track the sun while young and settle facing east once mature, which is worth remembering when you decide which side of the garden they'll be admired from.
The classic failure has nothing to do with growing and everything to do with eating: birds, mice and snails treat both the sown seed and emerging seedlings as a buffet. Cover rows with wire mesh or netting until plants are 20 cm tall, and bait or hand-pick snails after rain. Tall varieties in exposed spots appreciate a stake before they reach head height, not after the first big blow snaps them.
Sunflower at a glance
| Sowing depth | 8-12 mm |
|---|---|
| Plant spacing | 20-60 cm |
| Row spacing | 60-90 cm |
| Germination | 6-21 days |
| Days to maturity | 80-100 days |
| Frost tolerance | Hardy |
| Method | Raise Seedlings,Sow Direct |
Common questions
- When should I plant sunflower seeds in Australia?
- In temperate zones, sow direct from August to December. Early sowings germinate slowly in cool soil, while spring sowings emerge fast — staggering a few sowings gives flowers for months.
- How long do sunflowers take to flower?
- About 80–100 days from sowing, after germination of 6–21 days depending on soil temperature.
- Why didn't my sunflower seeds come up?
- Birds, mice and snails commonly take seed and seedlings before you ever see them, and seed in cold August soil can also rot. Cover the row with mesh until plants are established, and sow 8–12 mm deep into moist soil.
- Can sunflower seedlings handle frost?
- They tolerate the light frosts of a temperate spring, so August and September sowings are fine — just expect slower germination and early growth until the soil warms.
Track sunflower in your garden — sow dates, harvest countdowns, reminders. Free.
Add to my garden