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When to plant Corn in Rosebud County, MT

Rosebud County's short 145-day growing season means one Corn planting between May 25 and June 15. No fall crop in Zone 4b.

When to Plant Corn in Rosebud 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.

Rosebud County, Montana is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 3, giving you a growing season of approximately 145 days.

At an elevation of 6,448 feet, Rosebud County receives approximately 22.8 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.

Rosebud County, MT (Zone 4b) Short season
145 days
Last Spring Frost May 11
145 growing days
First Fall Frost October 3

Rosebud County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

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 Rosebud County's 145-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 2.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.9" 1.4" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Corn Planting Timeline — Rosebud County, MT

Corn Planting Calendar

Activity When Date Range
Direct Sow May 25 May 25 – Jun 15
Harvest July 27 Jul 27 – Sep 21

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

145 days in Rosebud County

Growing Tips for Rosebud 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 Rosebud County, MT?

Rosebud County is in Zone 4b with an average last frost of May 11. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rosebud County, MT?

Rosebud County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 3.

When should I plant Corn in Rosebud County, MT?

In Rosebud County, MT, plant Corn after the last frost (around May 11) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Rosebud County, MT for Corn?

Rosebud 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 Rosebud County's climate?

Yes — Corn grows well in Rosebud County's temperate climate. Rosebud County averages a 145-day frost-free season, with last frost around May 11 and first frost around October 3.

🌱

Your Rosebud County Garden Planner — Free

A 22-page printable planner built for Rosebud 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 Rosebud County, MT. Local conditions may vary. Last updated: July 2026.

Sources & credits

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