When to Plant Sunflower in Perth — Mediterranean Guide
Photo: Wikimedia Commons
Sunflowers are dual-purpose annual plants grown for edible seeds and ornamental beauty. They are among the easiest and most rewarding plants for Australian gardens, growing rapidly from seed and producing spectacular flower heads that attract pollinators. Important note: sunflowers exhibit allelopathy - they release chemicals through roots and decomposing plant matter that inhibit the growth of certain nearby plants.
Current Growing Conditions
Soil temperature: 21.9°C (optimal range: 15–35°C) ✓ Ready to plant
How to Grow Sunflower in Mediterranean Australia
When to Plant
Sow September-December. Excellent growing conditions with warm, dry summers.
- Soil
- Tolerates a wide range but prefers well-drained loam. Will grow in poor soil but produces larger heads in enriched soil. Remarkably drought-tolerant once established due to deep taproot.
- pH Range
- 6.0-7.5
- Sunlight
- Full sun - minimum 6 hours, ideally 8+. Sunflowers are heliotropic (young heads follow the sun) and need maximum light for best growth.
- Spacing
- 45cm apart, 75cm between rows
- Watering
- Water well at planting and during early growth. Once established (30cm+), sunflowers are surprisingly drought-tolerant. Deep weekly watering during head development and seed fill improves yield. Reduc
Companion plants: Corn, Squash/Pumpkin, Cucumber, Zinnia, Cosmos
Avoid planting near: Potato (allelopathic inhibition), Pole beans (allelopathic inhibition), Most brassicas, Grasses (allelopathically suppressed)
Mediterranean Growing Tips for Sunflower
Recommended Varieties
- Giant Russian
- Mammoth Grey Stripe
- Velvet Queen
- Lemon Queen
- Autumn Beauty
Key Challenges
- Summer drought stress during seed fill
- Bird damage
- Wind in exposed areas
Pro Tips
- Excellent sunflower zone - warm, dry conditions reduce disease
- Irrigate during seed fill for plump seeds
- Wind support (staking or group planting) needed in exposed coastal sites
Harvesting Sunflower
When ready: For EDIBLE SEEDS: back of head turns from green to yellow-brown, petals have dried and fallen, seeds are plump and hard, head droops downward. For ORNAMENTAL cut flowers: harvest when first ring of outer florets opens, before fully open.
How to harvest: For seeds: cut head with 30cm of stem. Hang upside down in dry, airy place inside a paper bag or with cloth underneath to catch falling seeds. Alternatively, rub seeds out of head by hand once dry (wear gloves - rough). For cut flowers: cut stems early morning, place in water immediately.
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