When to Plant Onion in Ohio County, KY
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.
Ohio County, Kentucky is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 28, giving you a growing season of approximately 203 days.
At an elevation of 1,511 feet, Ohio County receives approximately 54 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Onion during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Ohio County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.6
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 — Ohio County, KY
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 4 | Mar 4 – Mar 18 |
| Transplant Outdoors | April 8 | Apr 8 – Apr 22 |
| Direct Sow | March 25 | Mar 25 – Apr 15 |
| Fall Sowing | August 19 | Aug 19 – Sep 2 |
| Harvest | July 8 | Jul 8 – Aug 26 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| 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
6 – 7
USDA Zone
Zone 6b
Growing Season
203 days
Growing Tips for Ohio 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 Ohio County, KY?
Ohio County is in Zone 6b with an average last frost of April 8. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ohio County, KY?
Ohio County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 28.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Ohio County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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