Zinnia in Zone 3a & 3b

Zinnia elegans

When to plant zinnia in zone 3b

Zones 3a and 3b share the same average frost dates in our data, so this page covers both.

Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Zinnia tolerates either.

Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-4 ft.

Zinnias are about as forgiving as annual flowers get: direct-sow them after frost, give them sun, and they bloom fast and heavily with almost no fuss, throwing up daisy or dahlia-form flowers in almost every color except true blue on plants anywhere from 1 to 4 feet tall. They've also earned their spot in a vegetable garden on merit. They're one of the better-documented pollinator draws for nearby crops, beyond their good looks as a border filler.

How zinnia fits zone 3's season

Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Zinnia needs about 65 days from sowing to first harvest.

Good companions

• Tomato: Attracts pollinators and hoverflies that improve fruit set and help control aphids.
• Cucumber: Attracts pollinators that improve fruit set.

Where to buy zinnia 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 zinnia" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

← Back to the full zone 3b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Zinnia in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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