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When to plant Corn in Powder River County, MT

Plant Corn in Powder River County during the brief May 29–June 19 window. With 130 frost-free days, fall plantings can't mature before September 22.

When to Plant Corn in Powder River County, MT

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.

Powder River County, Montana is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 22, giving you a growing season of approximately 130 days.

At an elevation of 6,328 feet, Powder River County receives approximately 19.4 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Corn to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Corn successfully. Mulch heavily to conserve soil moisture.

Powder River County, MT (Zone 4b) Short season
130 days
Last Spring Frost May 15
130 growing days
First Fall Frost September 22

Powder River County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.9

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 Powder River County's 130-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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 1.8" 2.5" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Corn Planting Timeline — Powder River County, MT

Corn Planting Calendar

Activity When Date Range
Direct Sow May 29 May 29 – Jun 19
Harvest July 31 Jul 31 – Sep 25

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June Direct Sow
July Harvest
August Harvest
September Harvest
October
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 4b

📆 Growing Season

130 days in Powder River County

Growing Tips for Powder River 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 Powder River County, MT?

Powder River County is in Zone 4b with an average last frost of May 15. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Powder River County, MT?

Powder River County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 22.

When should I plant Corn in Powder River County, MT?

In Powder River County, MT, plant Corn after the last frost (around May 15) and before the first frost (around September 22). Best results when soil holds above 50°F.

What growing zone is Powder River County, MT for Corn?

Powder River County sits in USDA Zone 4b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Powder River County's climate?

Yes — Corn grows well in Powder River County's temperate climate. Powder River County averages a 130-day frost-free season, with last frost around May 15 and first frost around September 22.

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Your Powder River County Garden Planner — Free

A 22-page printable planner built for Powder River County (Zone 4b). 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 Powder River County, MT. Local conditions may vary. Last updated: July 2026.

Sources & credits

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