When to Plant Onion in Mobile County, AL
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Mobile County, Alabama is in USDA Zone 8b. The average last spring frost is March 3 and the first fall frost is November 24, giving you a growing season of approximately 266 days.
At an elevation of 101 feet, Mobile County receives approximately 48.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients.
Mobile County Soil Profile
Soil Type
Sandy Loam
Soil pH
4.8-6.1
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Plant Water Budget
Onion Planting Timeline — Mobile County, AL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 27 | Jan 27 – Feb 10 |
| Transplant Outdoors | March 3 | Mar 3 – Mar 17 |
| Direct Sow | February 17 | Feb 17 – Mar 10 |
| Fall Sowing | September 15 | Sep 15 – Sep 29 |
| Harvest | June 2 | Jun 2 – Jul 21 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
90–120 days
Soil pH
6 – 7
USDA Zone
Zone 8b
Growing Season
266 days
Growing Tips for Mobile County
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Mobile County, AL?
Mobile County is in Zone 8b with an average last frost of March 3. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mobile County, AL?
Mobile County, Alabama is in USDA Hardiness Zone 8b. The average last spring frost is March 3 and first fall frost is November 24.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mobile County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.
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