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When to Plant Onion in Greene County, MO

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.

Greene County, Missouri is in USDA Zone 6a. The average last spring frost is April 10 and the first fall frost is October 22, giving you a growing season of approximately 195 days.

At an elevation of 891 feet, Greene County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Onion during the growing season.

Greene County, MO (Zone 6a) Moderate season
195 days
Last Spring Frost April 10
195 growing days
First Fall Frost October 22

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: Jul 4 – Aug 22
Recommended (50%) ✓ Fits season (55 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jul 10 – Aug 28
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10

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
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 679 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Onion needs ~1,680 GDD — county provides 3,120 GDD Excellent fit

Onion Planting Timeline โ€” Greene County, MO

Onion Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Direct Sow March 27 Mar 27 โ€“ Apr 17
Fall Sowing August 13 Aug 13 โ€“ Aug 27
Harvest July 10 Jul 10 โ€“ Aug 28

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June โ€”
July Harvest
August Fall Sowing Harvest
September โ€”
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 6a

Growing Season

195 days

Growing Tips for Greene 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 Greene County, MO?

Greene County is in Zone 6a with an average last frost of April 10. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Greene County, MO?

Greene County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 10 and first fall frost is October 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Greene County gardeners in Zone 6a 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 Greene County, MO. Local conditions may vary. Last updated: April 2026.