Zone 4a planting calendar
Cold winters, short summers. Hardy greens thrive; warm crops need a head start indoors.
Coldest temps-30 to -25°F
Avg. last spring frostMay 15
Avg. first fall frostSep 18
Open the interactive calendar for Zone 4a →
The growing season in Zone 4a
Zone 4a has a coldest-winter range of -30 to -25°F and an average frost-free growing season of roughly 126 days — from the last spring frost around May 15 to the first fall frost around Sep 18. That is a moderate season that comfortably suits most vegetables, with time for a spring and a fall planting of the cool-season crops.
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 15, and the longer-season ones among them (melons, winter squash, full-size tomatoes) are the plants to watch against the 126-day window. Start those indoors on the schedule below so they have time to finish before fall frost returns.
What to plant in Zone 4a
Every crop below is timed to Zone 4a'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 Mar 27–Apr 10 Transplant outdoors May 22–May 29 |
| Pepper | Start seeds indoors Mar 13–Mar 27 Transplant outdoors May 29–Jun 5 |
| Lettuce | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 24–Aug 7 |
| Carrot | Direct sow outdoors Apr 24–May 29 Direct sow outdoors Jul 10–Jul 24 |
| Bush Bean | Direct sow outdoors May 15–Jun 12 |
| Cucumber | Start seeds indoors Apr 24–May 1 Transplant outdoors May 22–May 29 Direct sow outdoors May 22–Jun 5 |
| Zucchini | Direct sow outdoors May 15–Jun 5 |
| Spinach | Direct sow outdoors Apr 3–May 1 Direct sow outdoors Jul 24–Aug 14 |
| Kale | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 1–May 15 Direct sow outdoors May 1–May 29 Direct sow outdoors Jun 26–Jul 24 |
| Pea | Direct sow outdoors Apr 3–Apr 24 |
| Basil | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 22–Jun 5 |
| Cilantro | Direct sow outdoors Apr 24–May 22 Direct sow outdoors Jul 24–Aug 14 |
| Broccoli | Start seeds indoors Mar 27–Apr 10 Transplant outdoors May 1–May 15 Direct sow outdoors Jun 12–Jul 3 |
| Cabbage | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 1–May 15 |
| Cauliflower | Start seeds indoors Mar 27–Apr 10 Transplant outdoors May 1–May 15 |
| Brussels Sprouts | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 8–May 22 |
| Onion | Start seeds indoors Mar 6–Mar 20 Transplant outdoors Apr 17–May 1 |
| Garlic | Direct sow outdoors Aug 21–Sep 4 |
| Beet | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 10–Jul 24 |
| Radish | Direct sow outdoors Apr 17–May 29 Direct sow outdoors Jul 24–Aug 21 |
| Swiss Chard | Direct sow outdoors May 1–May 29 |
| Potato | Direct sow outdoors May 1–May 29 |
| Sweet Corn | Direct sow outdoors May 15–Jun 5 |
| Eggplant | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 29–Jun 5 |
| Pumpkin | Direct sow outdoors May 15–Jun 5 |
| Winter Squash | Direct sow outdoors May 15–Jun 5 |
| Arugula | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 24–Aug 21 |
| Leek | Start seeds indoors Mar 6–Mar 20 Transplant outdoors Apr 17–May 1 |
| Turnip | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 24–Aug 7 |
| Kohlrabi | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 24–Aug 7 |
| Okra | Start seeds indoors Apr 17–May 1 Direct sow outdoors May 22–Jun 5 |
| Celery | Start seeds indoors Mar 6–Mar 20 Transplant outdoors May 8–May 22 |
| Collard Greens | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 1–May 15 Direct sow outdoors Jun 26–Jul 24 |
| Mustard Greens | Direct sow outdoors Apr 17–May 15 Direct sow outdoors Jul 24–Aug 14 |
| Bok Choy | Direct sow outdoors Apr 24–May 15 Direct sow outdoors Jul 24–Aug 14 |
| Fennel | Direct sow outdoors May 1–May 29 Direct sow outdoors Jul 10–Jul 24 |
| Sweet Potato | Transplant outdoors May 29–Jun 12 |
| Parsnip | Direct sow outdoors May 1–May 29 |
| Asparagus | Transplant outdoors Apr 17–May 1 |
| Parsley | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 1–May 15 Direct sow outdoors May 1–May 29 |
| Dill | Direct sow outdoors May 1–May 29 Direct sow outdoors Jul 24–Aug 7 |
| Chives | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 1–May 15 |
| Thyme | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 15–May 29 |
| Oregano | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 15–May 29 |
| Sage | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 15–May 29 |
| Rosemary | Start seeds indoors Mar 6–Mar 20 Transplant outdoors May 29–Jun 12 |
| Mint | Transplant outdoors May 15–May 29 |
| Lavender | Start seeds indoors Mar 6–Mar 20 Transplant outdoors May 15–May 29 |
| Chamomile | Direct sow outdoors May 1–May 29 |
| Lemon Balm | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 15–May 29 |
| Tarragon | Transplant outdoors May 15–May 29 |
| Strawberry | Transplant outdoors Apr 17–May 1 |
| Watermelon | Start seeds indoors Apr 17–May 1 Transplant outdoors May 29–Jun 5 Direct sow outdoors May 22–Jun 5 |
| Cantaloupe | Start seeds indoors Apr 17–May 1 Transplant outdoors May 29–Jun 5 Direct sow outdoors May 22–Jun 5 |
| Ground Cherry | Start seeds indoors Mar 27–Apr 10 Transplant outdoors May 22–May 29 |
| Blueberry | Transplant outdoors Apr 17–May 1 |
| Raspberry | Transplant outdoors Apr 10–Apr 24 |
| Blackberry | Transplant outdoors Apr 10–Apr 24 |
| Rhubarb | Transplant outdoors Apr 10–Apr 24 |
| Currant | Transplant outdoors Apr 3–Apr 24 |
| Gooseberry | Transplant outdoors Apr 3–Apr 24 |
| Marigold | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 22–May 29 Direct sow outdoors May 15–May 29 |
| Zinnia | Start seeds indoors Apr 17–May 1 Transplant outdoors May 22–May 29 Direct sow outdoors May 15–May 29 |
| Sunflower | Direct sow outdoors May 15–Jun 5 |
| Cosmos | Direct sow outdoors May 15–May 29 |
| Nasturtium | Direct sow outdoors May 15–May 29 |
| Sweet Pea | Direct sow outdoors Apr 3–Apr 24 |
| Snapdragon | Start seeds indoors Mar 20–Apr 3 Transplant outdoors May 1–May 15 |
| Pansy | Start seeds indoors Mar 6–Mar 20 Transplant outdoors Apr 17–May 1 |
| Dahlia | Start seeds indoors Apr 17–May 1 Transplant outdoors May 22–May 29 |
| Calendula | Direct sow outdoors May 1–May 29 Direct sow outdoors Jul 24–Aug 7 |
| Poppy | Direct sow outdoors Apr 3–May 1 |
| Cornflower | Direct sow outdoors Apr 17–May 8 Direct sow outdoors Jul 24–Aug 7 |
| Aster | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 15–May 29 |
| Celosia | Start seeds indoors Apr 3–Apr 17 Transplant outdoors May 22–May 29 |
| Sweet Alyssum | Direct sow outdoors May 1–May 29 |
| Morning Glory | Direct sow outdoors May 15–May 29 |