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When to Plant Corn in Jefferson County, KS

Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

Jefferson County, Kansas is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.

At an elevation of 559 feet, Jefferson County receives approximately 23.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90ยฐF, providing good warmth for Corn during the growing season.

Jefferson County, KS (Zone 6a) Moderate season
193 days
Last Spring Frost April 14
193 growing days
First Fall Frost October 24

Jefferson 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 (73 days to spare)
Transplant: Apr 7 🍅 Harvest: Jun 9 – Aug 4
Recommended (50%) ✓ Fits season (74 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 11
Safe Start (90%) ✓ Fits season (76 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 24

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
0.6″/week
Watering frequency 1-2 times/week
Season total 994 gal / 100 sq ft
Drought risk

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

Corn needs ~1,400 GDD — county provides 3,377 GDD Excellent fit

Corn Planting Timeline โ€” Jefferson County, KS

Corn Planting Calendar

Activity When Date Range
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 23 Jun 23 โ€“ Aug 18

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May Direct Sow
June Harvest
July Harvest
August 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

60โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

193 days

Growing Tips for Jefferson County

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Level Up Your Garden

Frequently Asked Questions

When should I plant Corn in Jefferson County, KS?

Jefferson County is in Zone 6a with an average last frost of April 14. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jefferson County, KS?

Jefferson County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

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