WHEN TO PLANT SUNFLOWER SEEDS: A SEASONAL GROWING GUIDE

Sunflowers are among the easiest and most cheerful flowers to grow, adding height, color, and pollinator-friendly blooms to your garden. But timing matters: to get the tallest stalks and biggest flowers, you need to know the best time to plant sunflower seeds.

This guide covers when to plant sunflower seeds, depending on your climate and growing goals.

1. The Best Time of Year to Plant Sunflower Seeds

Sunflowers are warm-weather plants that thrive once the danger of frost has passed.

In most regions: Plant seeds in late spring to early summer (April–June).
Soil temperature: Wait until the soil warms to at least 55–60°F (13–16°C).
Frost-free timing: Seeds can be sown about 1–2 weeks after the last frost date in your area.

Tip: If you’re unsure of your local frost dates, check with a local extension service or garden center.

2. Planting Sunflowers in Different Climates

Cool climates (short summers): Start seeds indoors 2–3 weeks before the last frost, then transplant outdoors once soil warms.
Warm climates (long summers): You can direct-sow sunflower seeds outdoors from spring through early summer. Some gardeners even do successive plantings every 2–3 weeks for continuous blooms.
Tropical regions: Sunflowers can be planted almost year-round, but avoid peak rainy seasons to prevent rot.

3. Sunlight and Soil Conditions

To ensure success, plant sunflower seeds where they’ll get the right growing conditions:

Sunlight: Choose a spot with at least 6–8 hours of full sun daily.
Soil: Well-drained, loose soil enriched with compost works best. Sunflowers have deep roots, so loosen soil at least 2 feet down if possible.

4. Spacing and Depth for Planting

Depth: Sow seeds 1 inch deep.
Spacing:
- Small varieties: 6–12 inches apart.
- Tall/giant varieties: 18–24 inches apart.
Rows: Keep rows about 2–3 feet apart for air circulation.