Bismarck, ND · zone 4a · ~139 frost-free days
When to plant a garden in Bismarck.
In Bismarck, the typical last spring frost lands around May 12 and the first fall frost around Sep 28, giving you about 139 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 Bismarck, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Apr 7 to Jun 7 | May 19 to Jul 19 | — |
| Lettuce, leaf | — | Apr 4 to May 19 | Jul 15 to Sep 13 |
| Carrot | — | Apr 4 to May 7 | Jul 3 to Jul 29 |
| Bush Bean | — | May 12 to Jul 2 | Jun 14 to Jul 17 |
| Cucumber, slicing | — | May 19 to Aug 18 | May 28 to Jun 28 |
| Pepper, bell | Apr 16 to Jun 7 | May 28 to Jul 19 | — |
| Kale | Feb 21 to Mar 21 | Apr 4 to May 2 | Jun 28 to Aug 13 |
| Spinach | — | Mar 21 to May 2 | Jul 15 to Sep 2 |
Bismarck 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 Bismarck 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 58501 in about 60 seconds.