Gardening in zone 3b
In USDA zone 3b, the coldest winter night averages -35 to -30°F. The typical last spring frost is around May 17 and the first fall frost around Sep 24.
A zone tells you about winter cold, not about timing: across zone 3b, last spring frosts range from about May 12 to May 28, and first fall frosts from Sep 8 to Oct 1. Plan from your own frost dates where you can.
Zone 3b is common in: Minnesota, North Dakota, Montana
Zone 3b planting schedule
Dates below count from the zone’s typical frost dates, so treat them as a starting point. For dates set to your exact ZIP code, use the planting calendar.
| Crop | Start indoors | Plant or sow outside | Fall planting |
|---|---|---|---|
| Tomato | Around Apr 5 | Around May 31 | — |
| Pepper | Around Mar 22 | Around May 31 | — |
| Eggplant | Around Mar 22 | Around May 31 | — |
| Basil | Around Apr 5 | Around May 31 | — |
| Cucumber | Around Apr 26 | Around May 31 | — |
| Zucchini | Around Apr 26 | Around May 24 | — |
| Butternut Squash | Around Apr 26 | Around May 24 | — |
| Watermelon | Around Apr 26 | Around May 31 | — |
| Corn | — | Around May 17 | — |
| Green Bean | — | Around May 24 | — |
| Pea | — | Around Apr 5 | Around Jul 16 |
| Lettuce | — | Around Apr 19 | Around Aug 6 |
| Spinach | — | Around Apr 5 | Around Jul 30 |
| Kale | Around Apr 5 | Around May 17 | Around Jul 16 |
| Broccoli | Around Mar 22 | Around May 3 | Around Jun 18 |
| Cabbage | Around Apr 5 | Around May 17 | Around Jun 18 |
| Carrot | — | Around Apr 26 | Around Jul 9 |
| Beet | — | Around Apr 19 | Around Jul 16 |
| Radish | — | Around Apr 19 | Around Aug 13 |
| Onion | Around Mar 8 | Around Apr 26 | — |
| Potato | — | Around May 3 | — |
| Garlic | — | — | Around Oct 8 |
Zones: 2023 USDA Plant Hardiness Zone Map. Frost dates: NOAA NCEI U.S. Climate Normals 1991–2020 (50% chance of 32°F), middle value across the zone's ZIP codes.
Other zones: 4a · 4b · 5a · 5b · 6a · 6b · 7a · 7b · 8a · 8b · 9a · 9b · 10a