Sunflower Growing Guide

Helianthus annuus

Sunflower

Crop Rotation Group

Miscellaneous ●

Soil

Any sunny site with good drainage.

Position

Full sun.

Frost tolerant

Sunflower seedlings often escape damage from light frost, but sunflowers are warm-natured plants with no tolerance of freezing temperatures.

Feeding

Mix a light application of a balanced organic fertilizer into the soil prior to planting.

Companions

A rare "shelter" plant, sunflowers can be used to create shade for sun-stressed crops. Tall varieties can serve as trellises for transplanted runner beans seedlings (but not those grown from seed in the same area as sunflower seedlings are negatively allelopathic to competitors.)

Spacing

Single Plants: 11" (30cm) each way (minimum)
Rows: 11" (30cm) with 11" (30cm) row gap (minimum)

Sow and Plant

Sow sunflowers from late spring to early summer. Where summers are long and warm, make a second sowing for autumn harvest. Poke seeds into the soil about 1 inch (3 cm) deep and 3 inches (8 cm) apart. Thin to 12 inches (30 cm) apart in all directions for dwarf varieties. Extremely tall sunflowers or those that grow into multi-branched bushes may require 3 feet (1 meter) between plants.
Our Garden Planner can produce a personalised calendar of when to sow, plant and harvest for your area.

Notes

Explore different sunflower varieties, which vary in size, color, growth habit, and the culinary quality of the seeds.

Harvesting

Cut sunflower heads when some of the seeds inside the edges appear ripe and fall away when rubbed, or when birds start harvesting them for you. Store in a warm, dry place.

Troubleshooting

Sunflowers will twist around to face the south or west, seeking the most abundant source of sun, which may be away from your garden.

Planting and Harvesting Calendar

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Pests which Affect Sunflower