Mint (Spearmint) in Zone 4a & 4b
Mentha spicata
Yes, mint (spearmint) grows in zones 4a and 4b. Set out nursery plants May 15–May 22.
When to plant mint (spearmint) in zone 4b
Zones 4a and 4b share the same average frost dates, so this page covers both.
Method: Buy as a start: Buy as a nursery start and transplant outside. It's slow or unreliable from seed, so most gardeners skip seed-starting it entirely.
| Start indoors | Not started from seed; buy as a nursery start |
|---|---|
| Direct sow / transplant outside | May 15–May 22 |
| Estimated harvest | Jul 24–Jul 31 (~70 days after transplanting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Plant alongside it in zone 4b
These go outside within two weeks of mint (spearmint) in zone 4b, so one planting day can cover them.
- BasilMay 29–Jun 5
- BorageMay 15–May 22
- DillMay 8–May 15
- RosemaryMay 29–Jun 5
- American GinsengMay 15–May 22
- AniseMay 15–May 22
Spearmint is fast, tough, and useful as a companion plant, but it comes with the same warning every mint does: given open soil, it spreads aggressively by rhizome and will take over more of a bed than intended.
How mint (spearmint) fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Mint (spearmint) needs about 70 days from transplant to first harvest.
Mint (Spearmint) planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 4a & 4b (your zone) | Buy as a start | May 15–May 22 | Jul 24–Jul 31 |
| 5a & 5b | Buy as a start | May 10–May 17 | Jul 19–Jul 26 |
| 6a & 6b | Buy as a start | Apr 25–May 2 | Jul 4–Jul 11 |
| 7a & 7b | Buy as a start | Apr 10–Apr 17 | Jun 19–Jun 26 |
| 8a & 8b | Buy as a start | Mar 25–Apr 1 | Jun 3–Jun 10 |
| 9a & 9b | Buy as a start | Feb 15–Feb 22 | Apr 26–May 3 |
| 10a & 10bSpring window | Buy as a start | Feb–Apr | ~70 days after transplanting |
| Fall window | Buy as a start | Oct–Nov | ~70 days after transplanting |
Harvest dates are about 70 days after the sow or plant-out date.
Good companions
- Cabbage: Mint's scent is reputed to deter cabbage moths nearby, though this specific pairing hasn't been tested the way sage, dill, and thyme have: treat it as garden tradition.
- Tomato: Reputed to repel aphids near tomatoes.
Where to buy mint starts
Mint (spearmint) is almost always bought as a nursery start rather than seeded. Check a local nursery or garden center; we haven't vetted online start/plant suppliers yet.
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See it growing
Search YouTube for "growing mint (spearmint)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
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Growing Mint (Spearmint) in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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