Zone 3b planting calendar
Short cold-climate season; cold frames and transplants extend your window.
Coldest temps-35 to -30°F
Avg. last spring frostMay 20
Avg. first fall frostSep 12
Open the interactive calendar for Zone 3b →
The growing season in Zone 3b
Zone 3b has a coldest-winter range of -35 to -30°F and an average frost-free growing season of roughly 115 days — from the last spring frost around May 20 to the first fall frost around Sep 12. That is a short season — lean on cold-hardy crops and quick-maturing varieties, and give tender, long-season crops a generous indoor head start so they can finish in time.
The practical rhythm here is simple. Cool-season crops — peas, spinach, lettuce, radishes, and the brassicas — can go out around the last-frost date and again for a fall crop. Frost-tender crops like tomatoes, peppers, squash, and basil wait until after May 20, and the longer-season ones among them (melons, winter squash, full-size tomatoes) are the plants to watch against the 115-day window. Start those indoors on the schedule below so they have time to finish before fall frost returns.
What to plant in Zone 3b
Every crop below is timed to Zone 3b's frost dates. Follow a crop link for its full growing profile across all zones, or open the interactive calendar for the month-by-month view.
| Crop | When to plant |
|---|---|
| Tomato | Start seeds indoors Apr 1–Apr 15 Transplant outdoors May 27–Jun 3 |
| Pepper | Start seeds indoors Mar 18–Apr 1 Transplant outdoors Jun 3–Jun 10 |
| Lettuce | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 18–Aug 1 |
| Carrot | Direct sow outdoors Apr 29–Jun 3 Direct sow outdoors Jul 4–Jul 18 |
| Bush Bean | Direct sow outdoors May 20–Jun 17 |
| Cucumber | Start seeds indoors Apr 29–May 6 Transplant outdoors May 27–Jun 3 Direct sow outdoors May 27–Jun 10 |
| Zucchini | Direct sow outdoors May 20–Jun 10 |
| Spinach | Direct sow outdoors Apr 8–May 6 Direct sow outdoors Jul 18–Aug 8 |
| Kale | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 6–May 20 Direct sow outdoors May 6–Jun 3 Direct sow outdoors Jun 20–Jul 18 |
| Pea | Direct sow outdoors Apr 8–Apr 29 |
| Basil | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 27–Jun 10 |
| Cilantro | Direct sow outdoors Apr 29–May 27 Direct sow outdoors Jul 18–Aug 8 |
| Broccoli | Start seeds indoors Apr 1–Apr 15 Transplant outdoors May 6–May 20 Direct sow outdoors Jun 6–Jun 27 |
| Cabbage | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 6–May 20 |
| Cauliflower | Start seeds indoors Apr 1–Apr 15 Transplant outdoors May 6–May 20 |
| Brussels Sprouts | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 13–May 27 |
| Onion | Start seeds indoors Mar 11–Mar 25 Transplant outdoors Apr 22–May 6 |
| Garlic | Direct sow outdoors Aug 15–Aug 29 |
| Beet | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 4–Jul 18 |
| Radish | Direct sow outdoors Apr 22–Jun 3 Direct sow outdoors Jul 18–Aug 15 |
| Swiss Chard | Direct sow outdoors May 6–Jun 3 |
| Potato | Direct sow outdoors May 6–Jun 3 |
| Sweet Corn | Direct sow outdoors May 20–Jun 10 |
| Eggplant | Start seeds indoors Mar 25–Apr 8 Transplant outdoors Jun 3–Jun 10 |
| Pumpkin | Direct sow outdoors May 20–Jun 10 |
| Winter Squash | Direct sow outdoors May 20–Jun 10 |
| Arugula | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 18–Aug 15 |
| Leek | Start seeds indoors Mar 11–Mar 25 Transplant outdoors Apr 22–May 6 |
| Turnip | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 18–Aug 1 |
| Kohlrabi | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 18–Aug 1 |
| Okra | Start seeds indoors Apr 22–May 6 Direct sow outdoors May 27–Jun 10 |
| Celery | Start seeds indoors Mar 11–Mar 25 Transplant outdoors May 13–May 27 |
| Collard Greens | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 6–May 20 Direct sow outdoors Jun 20–Jul 18 |
| Mustard Greens | Direct sow outdoors Apr 22–May 20 Direct sow outdoors Jul 18–Aug 8 |
| Bok Choy | Direct sow outdoors Apr 29–May 20 Direct sow outdoors Jul 18–Aug 8 |
| Fennel | Direct sow outdoors May 6–Jun 3 Direct sow outdoors Jul 4–Jul 18 |
| Sweet Potato | Transplant outdoors Jun 3–Jun 17 |
| Parsnip | Direct sow outdoors May 6–Jun 3 |
| Asparagus | Transplant outdoors Apr 22–May 6 |
| Parsley | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 6–May 20 Direct sow outdoors May 6–Jun 3 |
| Dill | Direct sow outdoors May 6–Jun 3 Direct sow outdoors Jul 18–Aug 1 |
| Chives | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 6–May 20 |
| Thyme | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 20–Jun 3 |
| Oregano | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 20–Jun 3 |
| Sage | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 20–Jun 3 |
| Rosemary | Start seeds indoors Mar 11–Mar 25 Transplant outdoors Jun 3–Jun 17 |
| Mint | Transplant outdoors May 20–Jun 3 |
| Lavender | Start seeds indoors Mar 11–Mar 25 Transplant outdoors May 20–Jun 3 |
| Chamomile | Direct sow outdoors May 6–Jun 3 |
| Lemon Balm | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 20–Jun 3 |
| Tarragon | Transplant outdoors May 20–Jun 3 |
| Strawberry | Transplant outdoors Apr 22–May 6 |
| Watermelon | Start seeds indoors Apr 22–May 6 Transplant outdoors Jun 3–Jun 10 Direct sow outdoors May 27–Jun 10 |
| Cantaloupe | Start seeds indoors Apr 22–May 6 Transplant outdoors Jun 3–Jun 10 Direct sow outdoors May 27–Jun 10 |
| Ground Cherry | Start seeds indoors Apr 1–Apr 15 Transplant outdoors May 27–Jun 3 |
| Blueberry | Transplant outdoors Apr 22–May 6 |
| Raspberry | Transplant outdoors Apr 15–Apr 29 |
| Blackberry | Transplant outdoors Apr 15–Apr 29 |
| Rhubarb | Transplant outdoors Apr 15–Apr 29 |
| Currant | Transplant outdoors Apr 8–Apr 29 |
| Gooseberry | Transplant outdoors Apr 8–Apr 29 |
| Marigold | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 27–Jun 3 Direct sow outdoors May 20–Jun 3 |
| Zinnia | Start seeds indoors Apr 22–May 6 Transplant outdoors May 27–Jun 3 Direct sow outdoors May 20–Jun 3 |
| Sunflower | Direct sow outdoors May 20–Jun 10 |
| Cosmos | Direct sow outdoors May 20–Jun 3 |
| Nasturtium | Direct sow outdoors May 20–Jun 3 |
| Sweet Pea | Direct sow outdoors Apr 8–Apr 29 |
| Snapdragon | Start seeds indoors Mar 25–Apr 8 Transplant outdoors May 6–May 20 |
| Pansy | Start seeds indoors Mar 11–Mar 25 Transplant outdoors Apr 22–May 6 |
| Dahlia | Start seeds indoors Apr 22–May 6 Transplant outdoors May 27–Jun 3 |
| Calendula | Direct sow outdoors May 6–Jun 3 Direct sow outdoors Jul 18–Aug 1 |
| Poppy | Direct sow outdoors Apr 8–May 6 |
| Cornflower | Direct sow outdoors Apr 22–May 13 Direct sow outdoors Jul 18–Aug 1 |
| Aster | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 20–Jun 3 |
| Celosia | Start seeds indoors Apr 8–Apr 22 Transplant outdoors May 27–Jun 3 |
| Sweet Alyssum | Direct sow outdoors May 6–Jun 3 |
| Morning Glory | Direct sow outdoors May 20–Jun 3 |