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When to Plant Corn in Elmore County, ID

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.

Elmore County, Idaho is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 14, giving you a growing season of approximately 170 days.

At an elevation of 5,944 feet, Elmore County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Corn during the growing season.

Elmore County, ID (Zone 6a) Moderate season
170 days
Last Spring Frost April 27
170 growing days
First Fall Frost October 14

Elmore County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 11
Recommended (50%) ✓ Fits season (51 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 24
Safe Start (90%) ✓ Fits season (50 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – 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 1,450 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Corn needs ~1,280 GDD — county provides 2,720 GDD Excellent fit

Corn Planting Timeline โ€” Elmore County, ID

Corn Planting Calendar

Activity When Date Range
Direct Sow May 4 May 4 โ€“ May 25
Harvest July 6 Jul 6 โ€“ Aug 31

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 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

170 days

Growing Tips for Elmore 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 Elmore County, ID?

Elmore County is in Zone 6a with an average last frost of April 27. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Elmore County, ID?

Elmore County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Elmore County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Elmore County, ID. Local conditions may vary. Last updated: April 2026.