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When to Plant Corn in Tompkins County, NY

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.

Tompkins County, New York is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 11, giving you a growing season of approximately 154 days.

At an elevation of 309 feet, Tompkins County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Corn during the growing season.

Tompkins County, NY (Zone 5b) Moderate season
154 days
Last Spring Frost May 10
154 growing days
First Fall Frost October 11

Tompkins County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Transplant: May 1 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (35 days to spare)
Transplant: May 10 🍅 Harvest: Jul 12 – Sep 6
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: May 21 🍅 Harvest: Jul 23 – Sep 17

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Corn needs ~1,220 GDD — county provides 2,348 GDD Excellent fit

Corn Planting Timeline โ€” Tompkins County, NY

Corn Planting Calendar

Activity When Date Range
Direct Sow May 17 May 17 โ€“ Jun 7
Harvest July 19 Jul 19 โ€“ Sep 13

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 Direct Sow
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

154 days

Growing Tips for Tompkins 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

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Frequently Asked Questions

When should I plant Corn in Tompkins County, NY?

Tompkins County is in Zone 5b with an average last frost of May 10. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Tompkins County, NY?

Tompkins County, New York is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

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