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When to Plant Onion in Pratt County, KS

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.

Pratt County, Kansas is in USDA Zone 6a. The average last spring frost is April 15 and the first fall frost is October 24, giving you a growing season of approximately 192 days.

At an elevation of 852 feet, Pratt County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 89ยฐF, providing good warmth for Onion during the growing season.

Pratt County, KS (Zone 6a) Moderate season
192 days
Last Spring Frost April 15
192 growing days
First Fall Frost October 24

Pratt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jul 9 – Aug 27
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 2
Safe Start (90%) ✓ Fits season (55 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 15

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
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,706 gal / 100 sq ft
Drought risk

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

Onion needs ~1,759 GDD — county provides 3,216 GDD Excellent fit

Onion Planting Timeline โ€” Pratt County, KS

Onion Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 โ€“ Mar 25
Transplant Outdoors April 15 Apr 15 โ€“ Apr 29
Direct Sow April 1 Apr 1 โ€“ Apr 22
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest July 15 Jul 15 โ€“ Sep 2

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 โ€”
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 6a

Growing Season

192 days

Growing Tips for Pratt 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 Pratt County, KS?

Pratt County is in Zone 6a with an average last frost of April 15. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pratt County, KS?

Pratt County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 15 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pratt 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 Pratt County, KS. Local conditions may vary. Last updated: April 2026.