Impatiens in Zone 4a & 4b
Impatiens walleriana
When to plant impatiens 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. Impatiens needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 6–Mar 13 |
|---|---|
| Direct sow / transplant outside | May 29–Jun 5 |
| Estimated bloom | Aug 12–Aug 19 (~75 days after transplanting) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 0.5-2 ft.
Impatiens flowers reliably in shade, which almost nothing else here does. It also carries a disease problem worth understanding before you plant a whole bed of it.
How impatiens fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Impatiens needs about 75 days from transplant to first harvest.
Good companions
No standout companions recorded yet for Impatiens.
Where to buy impatiens seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing impatiens" 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 Impatiens in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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