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When to Plant Onion in Bell 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.

Bell County, Kentucky is in USDA Zone 6b. The average last spring frost is April 19 and the first fall frost is October 22, giving you a growing season of approximately 186 days.

At an elevation of 2,589 feet, Bell County receives approximately 46.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Onion during the growing season.

Bell County, KY (Zone 6b) Moderate season
186 days
Last Spring Frost April 19
186 growing days
First Fall Frost October 22

Bell County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Aug 29
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jul 19 – Sep 6
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Aug 2 – Sep 20

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

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Onion needs ~1,759 GDD — county provides 3,115 GDD Excellent fit

Onion Planting Timeline โ€” Bell County, KY

Onion Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors April 19 Apr 19 โ€“ May 3
Direct Sow April 5 Apr 5 โ€“ Apr 26
Fall Sowing August 13 Aug 13 โ€“ Aug 27
Harvest July 19 Jul 19 โ€“ Sep 6

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors
June โ€”
July Harvest
August Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

186 days

Growing Tips for Bell 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

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Bell County, KY?

Bell County is in Zone 6b with an average last frost of April 19. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bell County, KY?

Bell County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 19 and first fall frost is October 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Bell County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Bell County, KY. Local conditions may vary. Last updated: April 2026.