When to plant Onion in Washington County, GA
Washington County gardeners should plant Onion between March 7 and March 28 in spring. With Washington County's Zone 8b climate (last frost March 21), Onion needs 90–120 days to mature — plant by July 14 for a full harvest. A second sowing from September 2 to September 16 extends the harvest into fall.
When to Plant Onion in Washington 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.
Washington County, Georgia is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 11, giving you a growing season of approximately 235 days.
At an elevation of 277 feet, Washington County receives approximately 50.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°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.
Washington County Soil Profile
Soil Type
Clay Loam
Soil pH
5.5-6.3
Drainage
Well Drained
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.3" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.3" | 1" | 💧 Light watering |
| May | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jun | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Oct | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Nov | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Washington County, GA
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 14 | Feb 14 – Feb 28 |
| Transplant Outdoors | March 21 | Mar 21 – Apr 4 |
| Direct Sow | March 7 | Mar 7 – Mar 28 |
| Harvest | June 20 | Jun 20 – Aug 8 |
| Fall Sowing | September 2 | Sep 2 – Sep 16 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors |
| May | — |
| June | Harvest |
| July | Harvest |
| August | 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 8b
📆 Growing Season
235 days in Washington County
Growing Tips for Washington 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 Washington County, GA?
Washington County is in Zone 8b with an average last frost of March 21. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, GA?
Washington County, Georgia is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 11.
When should I plant Onion in Washington County, GA?
In Washington County, GA, plant Onion after the last frost (around March 21) and before the first frost (around November 11). Best results when soil holds above 50°F.
What growing zone is Washington County, GA for Onion?
Washington County sits in USDA Zone 8b. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Washington County's climate?
Yes — Onion grows well in Washington County's temperate climate. Washington County averages a 235-day frost-free season, with last frost around March 21 and first frost around November 11.
Your Washington County Garden Planner — Free
A 22-page printable planner built for Washington County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.