Duluth, MN · zone 4a · ~151 frost-free days
When to plant in Duluth: frost dates and zone 4a.
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 5 | May 21 to Jul 17 | — |
| 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 | — |
| Cucumber, slicing | — | May 21 to Jul 26 | — |
| Pepper, bell | Apr 18 to Jun 8 | May 30 to Jul 20 | — |
| 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.
Duluth planting questions
What planting zone is Duluth, MN?+
Duluth is in USDA hardiness zone 4a. Growing zone, gardening zone, and planting zone all mean the same thing: the USDA number, 4a here. It tells you what survives winter, not when to plant. Frost dates set your planting time, and the free planner uses your exact ZIP code's frost dates, which can differ by weeks across one metro.
When is the last frost date in Duluth?+
The typical last spring frost in Duluth, MN is around May 14. That is an average from local history, not a guarantee, so tender crops like tomatoes and peppers are safer with a week of buffer after it.
When is the first frost date in Duluth?+
The typical first fall frost in Duluth, MN arrives around Oct 12, closing a growing season of roughly 151 frost-free days. Count backward from it to find the last date a fall crop can still finish.
What can I plant now in Duluth?+
It depends on the date. Cool-season crops like lettuce, kale, and spinach go out weeks before the last frost; warm-season crops like tomatoes and peppers wait until after May 14. The table above shows each crop's window; the free planner turns your ZIP into an exact, dated calendar.