Snapdragon in Zone 4a & 4b
Antirrhinum majus
When to plant snapdragon in zone 4b
Zones 4a and 4b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. Snapdragon needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 13–Mar 20 |
|---|---|
| Direct sow / transplant outside | May 8–May 15 |
| Estimated bloom | Aug 6–Aug 13 (~90 days after transplanting) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.

Snapdragons are one of the few flowers here that tolerate a light frost, which makes their planting window a little more forgiving than most, though the long indoor lead time before that still catches people off guard. What you're waiting for is a 1- to 3-foot spike of two-lipped, dragon-mouth blooms in almost any color you'd want.
How snapdragon fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Snapdragon needs about 90 days from transplant to first harvest.
Good companions
No standout companions recorded yet for Snapdragon.
Where to buy snapdragon seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing snapdragon" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Snapdragon in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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