Zone 1a planting calendar
Arctic; an extremely short frost-free window. Stick to the hardiest greens and fast transplants under cover.
Coldest temps-60 to -55°F
Avg. last spring frostJun 15
Avg. first fall frostAug 15
Open the interactive calendar for Zone 1a →
The growing season in Zone 1a
Zone 1a has a coldest-winter range of -60 to -55°F and an average frost-free growing season of roughly 61 days — from the last spring frost around Jun 15 to the first fall frost around Aug 15. 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 Jun 15, and the longer-season ones among them (melons, winter squash, full-size tomatoes) are the plants to watch against the 61-day window. Start those indoors on the schedule below so they have time to finish before fall frost returns.
What to plant in Zone 1a
Every crop below is timed to Zone 1a'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 27–May 11 Transplant outdoors Jun 22–Jun 29 |
| Pepper | Start seeds indoors Apr 13–Apr 27 Transplant outdoors Jun 29–Jul 6 |
| Lettuce | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 20–Jul 4 |
| Carrot | Direct sow outdoors May 25–Jun 29 Direct sow outdoors Jun 6–Jun 20 |
| Bush Bean | Direct sow outdoors Jun 15–Jul 13 |
| Cucumber | Start seeds indoors May 25–Jun 1 Transplant outdoors Jun 22–Jun 29 Direct sow outdoors Jun 22–Jul 6 |
| Zucchini | Direct sow outdoors Jun 15–Jul 6 |
| Spinach | Direct sow outdoors May 4–Jun 1 Direct sow outdoors Jun 20–Jul 11 |
| Kale | Start seeds indoors May 4–May 18 Transplant outdoors Jun 1–Jun 15 Direct sow outdoors Jun 1–Jun 29 Direct sow outdoors May 23–Jun 20 |
| Pea | Direct sow outdoors May 4–May 25 |
| Basil | Start seeds indoors May 4–May 18 Transplant outdoors Jun 22–Jul 6 |
| Cilantro | Direct sow outdoors May 25–Jun 22 Direct sow outdoors Jun 20–Jul 11 |
| Broccoli | Start seeds indoors Apr 27–May 11 Transplant outdoors Jun 1–Jun 15 Direct sow outdoors May 9–May 30 |
| Cabbage | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 1–Jun 15 |
| Cauliflower | Start seeds indoors Apr 27–May 11 Transplant outdoors Jun 1–Jun 15 |
| Brussels Sprouts | Start seeds indoors May 4–May 18 Transplant outdoors Jun 8–Jun 22 |
| Onion | Start seeds indoors Apr 6–Apr 20 Transplant outdoors May 18–Jun 1 |
| Garlic | Direct sow outdoors Jul 18–Aug 1 |
| Beet | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 6–Jun 20 |
| Radish | Direct sow outdoors May 18–Jun 29 Direct sow outdoors Jun 20–Jul 18 |
| Swiss Chard | Direct sow outdoors Jun 1–Jun 29 |
| Potato | Direct sow outdoors Jun 1–Jun 29 |
| Sweet Corn | Direct sow outdoors Jun 15–Jul 6 |
| Eggplant | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 29–Jul 6 |
| Pumpkin | Direct sow outdoors Jun 15–Jul 6 |
| Winter Squash | Direct sow outdoors Jun 15–Jul 6 |
| Arugula | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 20–Jul 18 |
| Leek | Start seeds indoors Apr 6–Apr 20 Transplant outdoors May 18–Jun 1 |
| Turnip | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 20–Jul 4 |
| Kohlrabi | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 20–Jul 4 |
| Okra | Start seeds indoors May 18–Jun 1 Direct sow outdoors Jun 22–Jul 6 |
| Celery | Start seeds indoors Apr 6–Apr 20 Transplant outdoors Jun 8–Jun 22 |
| Collard Greens | Start seeds indoors May 4–May 18 Transplant outdoors Jun 1–Jun 15 Direct sow outdoors May 23–Jun 20 |
| Mustard Greens | Direct sow outdoors May 18–Jun 15 Direct sow outdoors Jun 20–Jul 11 |
| Bok Choy | Direct sow outdoors May 25–Jun 15 Direct sow outdoors Jun 20–Jul 11 |
| Fennel | Direct sow outdoors Jun 1–Jun 29 Direct sow outdoors Jun 6–Jun 20 |
| Sweet Potato | Transplant outdoors Jun 29–Jul 13 |
| Parsnip | Direct sow outdoors Jun 1–Jun 29 |
| Asparagus | Transplant outdoors May 18–Jun 1 |
| Parsley | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 1–Jun 15 Direct sow outdoors Jun 1–Jun 29 |
| Dill | Direct sow outdoors Jun 1–Jun 29 Direct sow outdoors Jun 20–Jul 4 |
| Chives | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 1–Jun 15 |
| Thyme | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 15–Jun 29 |
| Oregano | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 15–Jun 29 |
| Sage | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 15–Jun 29 |
| Rosemary | Start seeds indoors Apr 6–Apr 20 Transplant outdoors Jun 29–Jul 13 |
| Mint | Transplant outdoors Jun 15–Jun 29 |
| Lavender | Start seeds indoors Apr 6–Apr 20 Transplant outdoors Jun 15–Jun 29 |
| Chamomile | Direct sow outdoors Jun 1–Jun 29 |
| Lemon Balm | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 15–Jun 29 |
| Tarragon | Transplant outdoors Jun 15–Jun 29 |
| Strawberry | Transplant outdoors May 18–Jun 1 |
| Watermelon | Start seeds indoors May 18–Jun 1 Transplant outdoors Jun 29–Jul 6 Direct sow outdoors Jun 22–Jul 6 |
| Cantaloupe | Start seeds indoors May 18–Jun 1 Transplant outdoors Jun 29–Jul 6 Direct sow outdoors Jun 22–Jul 6 |
| Ground Cherry | Start seeds indoors Apr 27–May 11 Transplant outdoors Jun 22–Jun 29 |
| Blueberry | Transplant outdoors May 18–Jun 1 |
| Raspberry | Transplant outdoors May 11–May 25 |
| Blackberry | Transplant outdoors May 11–May 25 |
| Rhubarb | Transplant outdoors May 11–May 25 |
| Currant | Transplant outdoors May 4–May 25 |
| Gooseberry | Transplant outdoors May 4–May 25 |
| Marigold | Start seeds indoors May 4–May 18 Transplant outdoors Jun 22–Jun 29 Direct sow outdoors Jun 15–Jun 29 |
| Zinnia | Start seeds indoors May 18–Jun 1 Transplant outdoors Jun 22–Jun 29 Direct sow outdoors Jun 15–Jun 29 |
| Sunflower | Direct sow outdoors Jun 15–Jul 6 |
| Cosmos | Direct sow outdoors Jun 15–Jun 29 |
| Nasturtium | Direct sow outdoors Jun 15–Jun 29 |
| Sweet Pea | Direct sow outdoors May 4–May 25 |
| Snapdragon | Start seeds indoors Apr 20–May 4 Transplant outdoors Jun 1–Jun 15 |
| Pansy | Start seeds indoors Apr 6–Apr 20 Transplant outdoors May 18–Jun 1 |
| Dahlia | Start seeds indoors May 18–Jun 1 Transplant outdoors Jun 22–Jun 29 |
| Calendula | Direct sow outdoors Jun 1–Jun 29 Direct sow outdoors Jun 20–Jul 4 |
| Poppy | Direct sow outdoors May 4–Jun 1 |
| Cornflower | Direct sow outdoors May 18–Jun 8 Direct sow outdoors Jun 20–Jul 4 |
| Aster | Start seeds indoors May 4–May 18 Transplant outdoors Jun 15–Jun 29 |
| Celosia | Start seeds indoors May 4–May 18 Transplant outdoors Jun 22–Jun 29 |
| Sweet Alyssum | Direct sow outdoors Jun 1–Jun 29 |
| Morning Glory | Direct sow outdoors Jun 15–Jun 29 |