Annual Flower

When to Plant Zinnias in California

The cut-and-come-again champion. The more you cut zinnias, the more they bloom. A cottage garden essential.

The Short Answer

California's warm, dry climate grows stunning zinnias with minimal disease pressure. Inland gardens produce the most vibrant colors thanks to intense sun.

California Frost Dates

Your planting dates depend on which part of California you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Northern California Mountains 5a, 5b, 6a, 6b May 1 - May 25 Sep 20 - Oct 15
Central Valley 9a, 9b Feb 10 - Mar 1 Nov 15 - Dec 5
Southern California Coast 10a, 10b, 11a Jan 1 - Feb 1 Dec 10 - Jan 1
Bay Area 9b, 10a Jan 20 - Feb 15 Nov 25 - Dec 15

Zinnias Planting Schedule for California

Northern California Mountains (Zones 5a, 5b, 6a, 6b)

Average last frost: May 1 - May 25 · Average first frost: Sep 20 - Oct 15

Start Seeds Indoors
4 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Central Valley (Zones 9a, 9b)

Average last frost: Feb 10 - Mar 1 · Average first frost: Nov 15 - Dec 5

Start Seeds Indoors
4 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Southern California Coast (Zones 10a, 10b, 11a)

Average last frost: Jan 1 - Feb 1 · Average first frost: Dec 10 - Jan 1

Start Seeds Indoors
4 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Bay Area (Zones 9b, 10a)

Average last frost: Jan 20 - Feb 15 · Average first frost: Nov 25 - Dec 15

Start Seeds Indoors
4 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Growing Zinnias in California

State-Specific Growing Tips

Central Valley and inland: sow March through June. Coastal: sow May through July — zinnias need heat to thrive. Full sun is essential. California's dry climate means minimal powdery mildew compared to the humid East.

Recommended Varieties for California

Everything grows in California. Benary's Giant, State Fair, Queen Lime. California flower farms feature zinnia varieties at farmers markets statewide.

Common Challenges in California

Spider mites in hot, dry inland areas. Aphids on developing buds. Minimal disease in the dry climate.

Growing Tips

Water at the base to prevent powdery mildew. Cut flowers just above a leaf node to encourage more branching and blooms.

Companion Planting

Plant zinnias alongside these companions for better growth:

Tomatoes Peppers

The Bottom Line

Zinnias can be grown successfully in California with proper attention to regional frost dates and local growing conditions. Timing varies across the state — Northern California Mountains gardeners work with a last frost around May 1 - May 25, while Bay Area sees frost end around Jan 20 - Feb 15. Choose varieties suited to your region, amend your soil based on its specific needs, and monitor for the pests and diseases most common in your area. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Zinnias Growing Guide National planting guide with all states California Planting Calendar All plants for California Zinnias in Alabama Alabama planting dates Zinnias in Alaska Alaska planting dates Zinnias in Arizona Arizona planting dates Zinnias in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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