When to plant Sunflower in Cool Australia

Cool zone — applies to Hobart, Canberra, Ballarat, Orange, Armidale and similar areas. Growing elsewhere? Temperate · Subtropical · Tropical · Arid.

Sow sunflowers direct from October to December in the cool zone, once frosts have finished and the soil is warming — late October in milder spots, well into November around Canberra or Orange. Germination takes 6–21 days depending on soil temperature, and most varieties flower in 80–100 days, so a November sowing blooms from February. Plant seed 8–12 mm deep where it is to grow; sunflowers resent root disturbance. Spacing sets the show: 20 cm apart gives a massed screen of smaller blooms, while up to 60 cm suits big single-headed giants.

Sowing calendar — cool zone

Green months are your sowing window: October to December.

Growing notes

The cool zone grows superb sunflowers, but the compressed summer sets the rules. With last frosts running to late October or November around Canberra and Orange, and the first autumn frost due about late April, an 80–100 day flower has room — provided you sow at the right end of the window. October and November sowings bloom in high summer; push a giant variety into late December and it may be racing an April frost to the finish. Where a cold snap threatens young plants, bottle cloches carry seedlings through light frosts that would flatten unprotected ones.

Sow direct into full sun — a north-facing fence line is ideal and doubles as a windbreak, because summer westerlies across the tablelands will snap or lean tall single-stem varieties. Stake anything expected to pass head height at sowing time, not after it starts leaning.

The most common failure happens in week one: seeds and seedlings eaten before they ever get going. Cockatoos, rosellas, slugs and snails all rate sunflower seedlings highly, so cover rows with netting or wire guards until plants are 20 cm tall. After that they are tough — water deeply once a week rather than lightly and often, and the same birds will return for the seed heads in autumn, which is either a problem or the whole point.

Sunflower at a glance

Common questions

When do you plant sunflower seeds in cool climates in Australia?

Sow direct from October to December, after the last frost. In frostier towns like Canberra or Orange that often means waiting until November. Earlier sowings within the window flower in high summer.

Why do my sunflower seedlings keep disappearing?

Birds, slugs and snails eat sunflower seeds and seedlings in the first weeks. Cover the row with netting or wire guards until plants are about 20 cm tall, after which they are rarely troubled.

How long do sunflowers take to flower?

Most varieties flower 80–100 days after sowing, with germination taking 6–21 days depending on soil warmth. A November sowing typically blooms from February.

Is December too late to sow sunflowers in Ballarat?

December is the last month of the window and still works for quicker varieties, but a 100-day giant sown in late December will be finishing dangerously close to the April frosts. Sooner is safer.

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