USDA Zone 4b Planting Calendar (2026)
Zone 4b (-25 to -20°F) has an average last spring frost on May 5 and first fall frost on Oct 1 — about 149 growing days. Typical areas: Minneapolis MN, Burlington VT.
How to use the zone 4b planting calendar
Every planting date on this page is calculated from zone 4b's average frost dates. Because your last spring frost lands around May 5 and your first fall frost around Oct 1, you have roughly 149 frost-free days to work with — a short growing season. The table below lists, for each of 20 common vegetables, when to start seeds indoors, when to sow or transplant outdoors, and when you can expect your first harvest.
Frost dates are averages, not guarantees. In a cold year the last frost can arrive 1-2 weeks later, so keep row covers handy for tender seedlings in May. Click any vegetable name to open a detailed zone 4b guide with spacing, companions, container tips and troubleshooting.
Cool-season crops for zone 4b
These tolerate light frost and go out first, 2-4 weeks before your May 5 last frost, and again in late summer for a fall crop: lettuce, carrot, broccoli, spinach, kale, onion, garlic, potato, peas, radish, beet, cabbage, cauliflower.
Warm-season crops for zone 4b
These need warm soil and frost-free weather, so plant them after May 5: tomato, pepper, cucumber, corn, bush beans, summer squash, zucchini. In a short season, start the slowest ones indoors to be sure they ripen before Oct.
| Vegetable | Start Indoors | Sow / Transplant | Harvest From |
|---|---|---|---|
| Beet | — | Apr 7 | Jun 1 |
| 🥦 Broccoli | Mar 31 | Apr 21 | Jun 25 |
| 🫘 Bush Beans | — | May 12 | Jul 6 |
| 🥬 Cabbage | Mar 24 | Apr 21 | Jul 10 |
| 🥕 Carrot | — | Apr 14 | Jun 23 |
| 🥦 Cauliflower | Mar 24 | Apr 21 | Jul 5 |
| 🌽 Corn | — | May 19 | Aug 7 |
| 🥒 Cucumber | Apr 14 | May 19 | Jul 13 |
| 🧄 Garlic | — | Oct 20 | Jun 17 |
| 🥬 Kale | Mar 31 | Apr 14 | Jun 8 |
| 🥬 Lettuce | Apr 7 | Apr 14 | May 29 |
| 🧅 Onion | Feb 24 | Apr 7 | Jul 16 |
| 🟢 Peas | — | Mar 24 | May 23 |
| 🫑 Pepper | Mar 10 | May 19 | Jul 28 |
| 🥔 Potato | — | Apr 21 | Jul 20 |
| 🌶️ Radish | — | Apr 7 | May 5 |
| 🍃 Spinach | — | Mar 31 | May 10 |
| 🎃 Summer Squash | Apr 14 | May 12 | Jul 1 |
| 🍅 Tomato | Mar 24 | May 12 | Jul 26 |
| 🥒 Zucchini | Apr 14 | May 12 | Jul 1 |
Spring, summer and fall planting in zone 4b
Spring (May): As soon as the soil can be worked, direct sow hardy cool-season crops and set out frost-tolerant transplants. This is your window for peas, lettuce, spinach and the brassicas before summer heat arrives.
Early summer (after May 5): Once frost danger passes and soil warms past 60°F, transplant tomatoes, peppers and squash and direct sow beans and cucumbers. This is the heart of the zone 4b growing season.
Late summer to fall (before Oct 1):Sow a second round of quick cool-season crops for a fall harvest. Count back each crop's days-to-harvest from Oct 1 to find the latest safe sowing date, and use row covers to stretch the season a few extra weeks.
Zone 4b planting FAQ
What planting zone is Minneapolis MN?
Areas like Minneapolis MN, Burlington VT fall in USDA hardiness zone 4b, defined by an average annual minimum temperature of -25 to -20°F. Your average last spring frost is around May 5 and your first fall frost around Oct 1.
When is the last frost in zone 4b?
The average last spring frost in zone 4b is around May 5. Wait until after this date before transplanting warm-season crops like tomatoes, peppers and squash. Cool-season crops can go out 2-4 weeks earlier because they tolerate light frost.
How long is the growing season in zone 4b?
Zone 4b has roughly 149 frost-free days between the last spring frost (May 5) and first fall frost (Oct 1). That is a short season — focus on fast-maturing and cool-season crops, and start heat lovers indoors.
What vegetables grow best in zone 4b?
Reliable choices for zone 4b include cool-season crops such as lettuce, carrot, broccoli, spinach planted in early spring, and warm-season crops such as tomato, pepper, cucumber, corn planted after the last frost. See the full table below for exact dates.
Can I grow a fall garden in zone 4b?
Yes. With a first frost around Oct 1, you can plant a second round of quick cool-season crops in mid to late summer. Count back the days-to-harvest from Oct 1 to find your fall planting date.
When should I start seeds indoors in zone 4b?
Most warm-season seedlings are started indoors 6-8 weeks before the last frost — that means roughly May for zone 4b. Tomatoes, peppers and eggplant benefit most from an indoor head start in this zone.