As the seasons transition and temperatures fluctuate, gardeners across the United States eagerly await the arrival of spring and dread the chill of autumn. One crucial factor in successful gardening is understanding the first and last frost dates specific to your USDA Hardiness Zone. You can find your Zone by entering your zip code: on desktop at the link above in the black bar "My Growing Zone"; on mobile by linking to any project page and selecting "Find My Planting Zone" link at the top of the page.
Frost dates mark the beginning and end of the frost-free growing season, serving as a valuable reference point for garden planning. The last frost date in spring is the date after which the risk of frost is significantly reduced, making it safer to transplant tender plants outdoors. The first frost date in fall, on the other hand, signifies the return of colder temperatures and the potential for frost damage to sensitive vegetation.
The USDA Hardiness Zone Map divides the United States into 13 zones based on average minimum winter temperatures. Each zone is further divided into subsets "a" and "b," indicating slight temperature variations. Knowing your specific zone helps you determine the best plants to grow in your region and when to start planting. Park Seed's app, From Seed to Spoon, will calculate these dates for you and provide you with the ideal timing for garden tasks conveniently on your phone. And that's just one of the tools the app provides. It will also help you identify pests and beneficials, learn about the nutrients your garden provides and how they help your overall wellness or support specific health issues. Check it out!
| Zone | First Frost Date | Last Frost Date |
|---|---|---|
| 1a | July 15 - July 31 | June 1 - June 15 |
| 1b | July 15 - July 31 | June 1 - June 15 |
| 2a | September 1 - September 15 | May 1 - May 15 |
| 2b | September 1 - September 15 | May 1 - May 15 |
| 3a, 3b | September 15 - September 30 | April 15 - April 30 |
| 4a, 4b | October 1 - October 15 | April 15 - April 30 |
| 5a – 7a | October 15 - October 31 | April 1 - April 15 |
| 7b | November 1 - November 15 | March 15 - March 31 |
| 8a | November 15 - November 30 | March 1 - March 15 |
| 8b | November 15 - November 30 | February 15 - February 28 |
| 9a | December 1 - December 15 | February 1 - February 15 |
| 9b | December 1 - December 15 | January 15 - January 31 |
| 10a, 10b | December 15 - December 31 | January 1 - January 15 |
| 11a – 13 | Frost-free year-round | Frost-free year-round |
Understanding your USDA Hardiness Zone's first and last frost dates empowers you to make informed decisions about when to start planting, transplant, and prepare for the colder months. If you prefer to have those dates calculated for you (yes, please!), get our app From Seed to Spoon.
