Alabama Frost Dates & Growing Season Guide
Alabama (AL) spans USDA hardiness zones 7b, 8a, 8b, with growing seasons ranging from 222 days in Huntsville to 291 days in Mobile. The average growing season across the state is approximately 253 days.
Alabama City Frost Dates
The table below shows the average last spring frost date, first fall frost date, growing season length, and USDA hardiness zone for each city. Click a city name for detailed planting calendars and zone information.
| City | Last Spring Frost | First Fall Frost | Growing Season | Zone | Min Temp |
|---|---|---|---|---|---|
| Birmingham | March 19 | November 15 | 241 days | 7b | 5°F |
| Montgomery | March 8 | November 21 | 258 days | 8a | 10°F |
| Mobile | February 17 | December 5 | 291 days | 8b | 15°F |
| Huntsville | March 28 | November 5 | 222 days | 7b | 5°F |
Planting Windows for Alabama
Based on average frost dates, here are the recommended planting windows for each city. The indoor seed start date is approximately seven weeks before the last spring frost. Transplanting should occur about two weeks after the last frost. The last direct sow date for fall crops is ten weeks before the first fall frost.
| City | Start Seeds Indoors | Transplant After | Last Direct Sow |
|---|---|---|---|
| Birmingham | January 30 | April 2 | September 6 |
| Montgomery | January 19 | March 22 | September 12 |
| Mobile | December 30 | March 2 | September 26 |
| Huntsville | February 8 | April 11 | August 27 |
Gardening in Alabama
Alabama gardeners benefit from a long growing season and warm summers that support two or even three plantings of quick-maturing crops like bush beans and lettuce. The state's humid subtropical climate makes fungal disease management a priority, so space plants for good airflow, water at the base rather than overhead, and consider fungicide-resistant varieties for tomatoes and squash. Fall gardening is excellent here, with cool-season crops like broccoli, kale, and carrots performing well from September through February in the southern part of the state.
Understanding Alabama's Hardiness Zones
Alabama includes USDA hardiness zones 7b, 8a, 8b. These zones indicate the average annual extreme minimum winter temperature for each area, which determines which perennial plants, trees, and shrubs can survive winter without protection. When purchasing trees, shrubs, or perennial flowers, always check that the plant is rated for your hardiness zone or a lower (colder) zone number.
Tips for Using Alabama Frost Dates
These frost dates represent long-term averages and should be treated as guidelines rather than guarantees. In any given year, the actual last spring frost or first fall frost may arrive one to three weeks earlier or later than the average. Factors that affect your specific location include elevation above the city center, proximity to water, slope direction, and whether you are in an urban or rural area. South-facing slopes and areas near large pavement or building masses tend to be warmer than surrounding open land. Low-lying valleys and exposed hilltops are often colder than mid-slope positions.
To protect against late spring frosts, keep row cover fabric, old bed sheets, or frost blankets on hand. Monitor your local weather forecast daily as the average frost date approaches. When frost is predicted after you have transplanted, covering plants in the late afternoon traps ground heat and can protect against temperatures down to about 28 degrees Fahrenheit. For fall season extension, the same covers protect mature plants from early frosts, often buying several additional weeks of harvest.