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When to Plant Zinnia in Hawaii

Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Hawaii spans USDA hardiness zones 11a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Zinnia planting dates based on your local frost dates.

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Zinnia Planting Calendar for Hawaii

Zone 11a ~364 day growing season · Full guide →

Last frost: January 1 · First frost: December 31 · 364 day season

Activity When Date Range
Start Indoors December 4 Dec 4 – Dec 18
Transplant Outdoors November 6 Nov 6 – Nov 20
Direct Sow November 6 Nov 6 – Nov 27
Bloom January 15 Jan 15 – Aug 27

Growing Tips for Hawaii

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

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Frequently Asked Questions

When should I plant Zinnia in Hawaii?

Planting dates for Zinnia in Hawaii depend on your USDA zone. Hawaii spans zones 11a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Hawaii for planting?

Hawaii contains USDA hardiness zones 11a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: June 2026.