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When to plant Corn in Idaho County, ID

Plant Corn in Idaho County, between June 5 and June 26 — the only viable window. Zone 6b's short season (114 frost-free days) rules out a fall crop.

When to Plant Corn in Idaho County, ID

Corn

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.

Idaho County, Idaho is in USDA Zone 6b. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 6,736 feet, Idaho County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Corn to ensure they mature before fall.

Idaho County, ID (Zone 6b) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20

Idaho County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

How Much Corn to Grow

1-2 ears
Average yield per plant
15
Plants per person
30 sq ft
Space per person

For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Idaho County's 114-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Corn

Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Idaho County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Corn Planting Timeline — Idaho County, ID

Corn Planting Calendar

Activity When Date Range
Direct Sow June 5 Jun 5 – Jun 26
Harvest August 7 Aug 7 – Oct 2

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

114 days in Idaho County

Growing Tips for Idaho 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Idaho County, ID?

Idaho County is in Zone 6b with an average last frost of May 29. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Idaho County, ID?

Idaho County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 29 and first fall frost is September 20.

When should I plant Corn in Idaho County, ID?

In Idaho County, ID, plant Corn after the last frost (around May 29) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Idaho County, ID for Corn?

Idaho County sits in USDA Zone 6b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Idaho County's climate?

Yes — Corn grows well in Idaho County's temperate climate. Idaho County averages a 114-day frost-free season, with last frost around May 29 and first frost around September 20.

🌱

Your Idaho County Garden Planner — Free

A 22-page printable planner built for Idaho County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.