Sunflowers are a warm-season crop. The trick is to sow once frost has passed and the soil has warmed — which lands at very different times around the world.
| Where you are | Best sowing months | Usually blooms |
|---|---|---|
| UK & Ireland | Apr–May (start indoors late Mar) | Jul–Sep |
| Northern & Central Europe | Apr–May | Jul–Sep |
| Southern / Mediterranean Europe | Mar–May | Jun–Sep |
| North America — cooler zones | May–Jun, after last frost | Aug–Sep |
| North America — warmer zones | Apr–May | Jul–Sep |
| Australia & New Zealand | Sep–Dec (spring–early summer) | Dec–Mar |
| South Africa | Sep–Nov | Dec–Mar |
| Southern South America | Sep–Nov | Dec–Mar |
| Tropical regions | Cooler / drier season; avoid sowing into extreme heat or heavy rain | ~10–12 weeks after sowing |
If you're in the Southern Hemisphere, your season is the mirror image of the north: while UK growers are sowing in April–May, yours comes around September–November, with the tall blooms arriving over your summer (December–March). That's part of what makes a worldwide contest fun — there's almost always a sunflower season happening somewhere.
Most sunflowers take roughly 11–18 weeks from sowing to full flower, depending on the variety and your climate. Giant varieties tend to be at the longer end — another reason to sow as early as your frost allows, to give them the whole season to stretch.
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