When to plant Onion in Cobb County, GA
Cobb County's climate puts the Onion spring window between March 17 and April 7. most warm-season crops establish quickly once soil holds above 60°F. A second sowing from August 23 to September 6 extends the harvest into fall.
When to Plant Onion in Cobb County, GA
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.
Cobb County, Georgia is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is November 1, giving you a growing season of approximately 215 days.
At an elevation of 387 feet, Cobb County receives approximately 57.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 89°F, providing good warmth for Onion during the growing season. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Cobb County Soil Profile
Soil Type
Clay Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Onion Planting Timeline — Cobb County, GA
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | March 31 | Mar 31 – Apr 14 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | June 30 | Jun 30 – Aug 18 |
| Fall Sowing | August 23 | Aug 23 – Sep 6 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| 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
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 8a
📆 Growing Season
215 days in Cobb County
Growing Tips for Cobb 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
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Cobb County, GA?
Cobb County is in Zone 8a with an average last frost of March 31. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cobb County, GA?
Cobb County, Georgia is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is November 1.
When should I plant Onion in Cobb County, GA?
In Cobb County, GA, plant Onion after the last frost (around March 31) and before the first frost (around November 1). Best results when soil holds above 50°F.
What growing zone is Cobb County, GA for Onion?
Cobb County sits in USDA Zone 8a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Cobb County's climate?
Yes — Onion grows well in Cobb County's temperate climate. Cobb County averages a 215-day frost-free season, with last frost around March 31 and first frost around November 1.
Your Cobb County Garden Planner — Free
A 22-page printable planner built for Cobb County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.