Duluth, MN · zone 4a · ~151 frost-free days
When to plant a garden in Duluth.
In Duluth, the typical last spring frost lands around May 14 and the first fall frost around Oct 12, giving you about 151 frost-free days. Cool-season crops go out before the last frost; warm-season crops wait until after it.
The 2026 windows
Sow dates for Duluth, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Apr 9 to Jun 9 | May 21 to Jul 21 | — |
| Lettuce, leaf | — | Apr 6 to May 21 | Jul 29 to Sep 27 |
| Carrot | — | Apr 6 to May 9 | Jul 17 to Aug 12 |
| Bush Bean | — | May 14 to Jul 4 | Jun 28 to Jul 31 |
| Cucumber, slicing | — | May 21 to Aug 20 | Jun 11 to Jul 12 |
| Pepper, bell | Apr 18 to Jun 9 | May 30 to Jul 21 | — |
| Kale | Feb 23 to Mar 23 | Apr 6 to May 4 | Jul 12 to Aug 27 |
| Spinach | — | Mar 23 to May 4 | Jul 29 to Sep 16 |
Duluth sits in Zone 4a, but two gardens in the same city can be a week or two apart. The planner works from your ZIP code's frost dates, not the zone, so the dates land right for your block, not the metro average.
Build your Duluth garden plan.
Tell the free planner what you want to eat and who you're feeding. It returns plant counts, spacing, and frost-safe sow dates for ZIP 55802 in about 60 seconds.