USDA Zone 4b planting calendar
In USDA Zone 4b, the average last spring frost is around 05/10 and the first fall frost around 09/30, giving roughly a 141-day growing season. Plant cool-season crops from late winter; warm-season crops after the last frost.
Last frost ~05/10
First frost ~09/30
~141-day season
51 NOAA stations
The year in Zone 4b
What to plant now (September)
No sowing or transplanting tasks land in September for this zone from our current crop list.
All crops in Zone 4b
| Crop | Start indoors | Transplant / sow | Sow for fall |
|---|---|---|---|
| Tomatoes | April 9 – April 16 | May 14 – May 28 | — |
| Peppers | March 29 | May 17 – May 31 | — |
| Eggplant | April 2 – April 16 | May 21 – June 4 | — |
| Basil | April 9 | May 14 – May 28 | — |
| Broccoli | March 22 – March 29 | April 12 – April 26 | June 21 – July 5 |
| Cabbage | March 1 – March 15 | April 5 – April 19 | May 12 – May 26 |
| Cauliflower | March 15 – March 29 | April 19 – May 3 | June 26 – July 10 |
| Brussels Sprouts | March 8 – March 22 | April 12 – April 26 | — |
| Kale | March 1 – March 15 | April 5 – April 19 | July 1 – July 15 |
| Lettuce | March 12 – March 19 | April 9 – April 23 | June 16 – June 30 |
| Spinach | — | April 2 – April 16 | July 26 – August 9 |
| Onions | February 1 – February 15 | April 5 – April 19 | — |
| Leeks | February 8 – February 22 | April 12 – April 26 | — |
| Swiss Chard | March 15 – March 22 | April 19 – May 3 | — |
| Radishes | — | April 12 – April 26 | August 10 – August 24 |
| Turnips | — | April 12 – April 26 | July 11 – July 25 |
| Beets | — | April 19 – May 3 | July 6 – July 20 |
| Carrots | — | May 3 – May 17 | June 6 – June 20 |
| Peas | — | March 29 – April 12 | July 1 – July 15 |
| Beans | — | May 10 – May 24 | — |
| Sweet Corn | — | May 10 – May 24 | — |
| Cucumbers | April 23 – April 30 | May 14 – May 28 | — |
| Summer Squash & Zucchini | April 26 – May 3 | May 17 – May 31 | — |
| Winter Squash | April 26 – May 3 | May 17 – May 31 | — |
| Pumpkins | April 26 – May 3 | May 17 – May 31 | — |
| Melons | April 26 – May 3 | May 17 – May 31 | — |
| Okra | April 19 – May 3 | May 24 – June 7 | — |
| Potatoes | — | April 23 – May 7 | — |
| Parsley | February 12 – February 19 | April 16 – April 30 | — |
| Collards | March 1 – March 15 | April 5 – April 19 | June 16 – June 30 |
| Watermelon | April 26 – May 3 | May 17 – May 31 | — |
| Sweet Potatoes | — | May 14 – May 28 | — |
| Celery | February 22 – March 8 | May 10 – May 24 | — |
| Kohlrabi | March 1 – March 15 | April 5 – April 19 | — |
| Artichoke | February 15 – March 15 | May 3 – May 17 | — |
| Asparagus | — | April 9 – April 23 | — |
| Cilantro | — | May 10 – May 24 | — |
| Dill | — | April 23 – May 7 | — |
| Oregano | March 8 – March 22 | May 10 – May 24 | — |
| Sage | March 22 – April 5 | May 10 – May 24 | — |
| Thyme | March 8 – March 22 | May 10 – May 24 | — |
Fall bulb planting in Zone 4b
| Crop | Plant cloves (fall) | Harvest |
|---|---|---|
| Garlic | October 4 – October 18 | Following summer |
Last verified 2026-09-12. Frost: NOAA NCEI 1991–2020 Climate Normals. Zone: USDA 2023 Plant Hardiness Zone Map (PRISM-derived). Planting rules: UNH Extension, Johnny's Selected Seeds, UGA Extension.