Petunia in Zone 10a & 10b

Petunia × hybrida

When to plant petunia in zone 10b

Zones 10a and 10b share the same average frost dates in our data, so this page covers both.

Method: Start indoors: Start indoors from seed, then transplant outside. Petunia needs a head start most zones can't give it by direct-sowing alone.

Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 0.5-1 ft.

Zone 10b dates sourced from growinginthegarden.com.

Petunias take the longest lead time of any flower on this list. Seed goes in about 9 weeks before last frost, and it needs light to germinate, so it's surface-sown rather than buried. That long runway is the price for having sizable, blooming plants ready to set out once the weather turns: a trailing or mounding 6- to 12-inch plant covered in trumpet-shaped flowers across a wide color range.

How petunia fits zone 10's season

Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Petunia needs about 70 days from transplant to first harvest.

Good companions

No standout companions recorded yet for Petunia.

Where to buy petunia seeds

• Botanical Interests
• True Leaf Market
• Burpee
• High Mowing Organic Seeds

See why we recommend these suppliers →

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See it growing

Search YouTube for "growing petunia" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

← Back to the full zone 10b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Petunia in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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