Zone 1a Planting Calendar
Zone 1a has an average minimum temperature range of -60°F to -55°F. The average last spring frost is around June 15 and the first fall frost is around August 15, giving you approximately 61 days in the growing season.
There are 3 plants in our database that grow well in Zone 1a.
States That Include Zone 1a
Many states span multiple zones. The states highlighted below contain areas classified as Zone 1a.
Growing Season Comparison
All Planting Windows at a Glance
This chart shows when to start, transplant, sow, and harvest every plant in Zone 1a.
Vegetables for Zone 1a
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Cabbage | May 4 | Jun 8 | Jun 15 | Aug 17 – Oct 12 | 60–100 |
| Microgreens | May 4 | Jun 8 | Jun 15 | Jun 22 – Jul 20 | 7–21 |
| Savoy Cabbage | May 4 | Jun 8 | Jun 15 | Aug 24 – Oct 19 | 70–110 |
Recommended for Your Garden
Full-spectrum LED lights for starting seeds indoors when daylight is limited.
Warm soil for faster germination of heat-loving crops like tomatoes and peppers.
Protect plants from frost, wind, and pests while letting light and water through.
Frequently Asked Questions
What can I grow in Zone 1a?
Zone 1a supports 3 plants in our database including vegetables, herbs, fruits, and flowers. With a 61-day growing season (last frost ~June 15, first frost ~August 15), you can grow most common garden crops with proper timing.
What is Zone 1a?
USDA Zone 1a has an average annual minimum temperature of -60°F to -55°F.
When is the last frost in Zone 1a?
The average last spring frost in Zone 1a is approximately June 15. The first fall frost averages around August 15, giving a growing season of about 61 days. These dates are based on 50% probability — plan for some year-to-year variation.
