Decatur, AL Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Decatur, Alabama.
Gardening in Decatur
The River City sits on the Tennessee River in the heart of the Tennessee Valley. TVA's legacy includes agricultural development that still benefits the region.
Zone 7b with 222 frost-free days. The Tennessee Valley provides fertile growing conditions and river-moderated temperatures. North Alabama's climate supports excellent four-season gardening.
The Tennessee Valley's agricultural heritage, anchored by TVA's development programs, created the infrastructure that home gardeners now benefit from.
What This Means for Decatur Gardeners
The average last spring frost in Decatur is around March 28, and the average first fall frost arrives around November 5. That gives you approximately 222 frost-free days to work with.
That's a generous season. You have time for full-size tomatoes, long-season peppers, and even watermelons without the anxiety of racing the frost. Start warm-season seeds indoors 6-8 weeks before your last frost to hit the ground running. Fall planting is your second opportunity — garlic, kale, lettuce, and broccoli all go in 8-10 weeks before your first frost for harvest into late autumn.
These dates are based on NOAA 30-year Climate Normal data for the Decatur area. Your actual frost dates could shift 2-3 weeks in either direction in any given year. Learn more about our data sources.
What to Grow in Decatur
Decatur's 222-day growing season is generous — long enough for two full growing windows (spring and fall) with warm-season crops between them. You can grow the full range of vegetables, herbs, and flowers with proper timing. Focus on heat-tolerant varieties for midsummer and cool-season crops for extended fall harvests. Recommended starting points: tomatoes, peppers, beans, cucumbers, squash, garlic, kale, and sunflowers.
See the full Alabama planting guide for all 40 plants: Alabama Planting Calendar. Or enter your zip code for exact planting dates personalized to Decatur.
More About Zone 7B
Decatur is in USDA Hardiness Zone 7B, which means average annual extreme minimum temperatures between 5°F to 10°F. View the full Zone 7B planting guide.
See the complete planting calendar for Alabama: Alabama Planting Calendar.
Other Cities in Alabama
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Decatur area. They represent historical averages, not predictions. In any given year, the actual last frost could be 2-3 weeks earlier or later. Microclimates within Decatur (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Cool-season crops go in 3-4 weeks before your last frost (March 28). Warm-season crops wait until 2 weeks after. You have time for a fall round too — plant cool-season crops again in late summer for harvest into autumn. Enter your zip code for exact dates.