Zucchini in Zone 3a & 3b
Cucurbita pepo
When to plant zucchini 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. Zucchini tolerates either.
| Start indoors | May 9–May 16 |
|---|---|
| Direct sow / transplant outside | Jun 6–Jun 13 |
| Estimated harvest | Jul 26–Aug 2 (~50 days after planting) |
Spacing: about 4 square feet per plant (square-foot-gardening spacing). Mature height: 2-3 ft.

Zucchini's reputation for overwhelming a garden is well-earned: a single healthy plant can produce more squash than most households can eat, which is exactly why our planting calendar puts just one plant per square foot rather than clustering several together.
How zucchini fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Zucchini needs about 50 days from sowing to first harvest.
Good companions
- Marigold: Marigolds deter squash bugs and beetles.
- Nasturtium: Nasturtium is a trap crop that draws aphids away from squash.
Where to buy zucchini seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing zucchini" 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 Zucchini in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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