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When to Plant Corn in Northumberland County, PA

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.

Northumberland County, Pennsylvania is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 26, giving you a growing season of approximately 192 days.

At an elevation of 324 feet, Northumberland County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Corn during the growing season.

Northumberland County, PA (Zone 6a) Moderate season
192 days
Last Spring Frost April 17
192 growing days
First Fall Frost October 26

Northumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (70 days to spare)
Transplant: Apr 13 🍅 Harvest: Jun 15 – Aug 10
Recommended (50%) ✓ Fits season (73 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 14
Safe Start (90%) ✓ Fits season (65 days to spare)
Transplant: May 7 🍅 Harvest: Jul 9 – Sep 3

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 180 gal / 100 sq ft
Corn needs ~1,460 GDD — county provides 3,504 GDD Excellent fit

Corn Planting Timeline โ€” Northumberland County, PA

Corn Planting Calendar

Activity When Date Range
Direct Sow April 24 Apr 24 โ€“ May 15
Harvest June 26 Jun 26 โ€“ Aug 21

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

192 days

Growing Tips for Northumberland 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 Northumberland County, PA?

Northumberland County is in Zone 6a with an average last frost of April 17. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Northumberland County, PA?

Northumberland County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 26.

๐ŸŒฑ

Plan Your Garden with Confidence

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