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When to Plant Corn in Armstrong 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.

Armstrong County, Pennsylvania is in USDA Zone 5b. The average last spring frost is April 29 and the first fall frost is October 18, giving you a growing season of approximately 172 days.

At an elevation of 213 feet, Armstrong County receives approximately 49.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Corn during the growing season.

Armstrong County, PA (Zone 5b) Moderate season
172 days
Last Spring Frost April 29
172 growing days
First Fall Frost October 18

Armstrong County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Aug 22
Recommended (50%) ✓ Fits season (53 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 26
Safe Start (90%) ✓ Fits season (47 days to spare)
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 16

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Corn needs ~1,160 GDD — county provides 2,494 GDD Excellent fit

Corn Planting Timeline โ€” Armstrong County, PA

Corn Planting Calendar

Activity When Date Range
Direct Sow May 6 May 6 โ€“ May 27
Harvest July 8 Jul 8 โ€“ Sep 2

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

Month-by-Month Timeline

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

60โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

172 days

Growing Tips for Armstrong 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 Armstrong County, PA?

Armstrong County is in Zone 5b with an average last frost of April 29. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Armstrong County, PA?

Armstrong County, Pennsylvania is in USDA Hardiness Zone 5b. The average last spring frost is April 29 and first fall frost is October 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Armstrong County gardeners in Zone 5b 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 Armstrong County, PA. Local conditions may vary. Last updated: April 2026.