When to plant Corn in Forsyth, MT
In Forsyth, Corn is a single-season spring crop — there's no second fall window. Plant May 25–June 15 for an 60–100-day harvest, finishing well before the October 3 first frost.
When to Plant Corn in Forsyth, MT
Your July planting checklist for Rosebud County, Montana
Your garden in Rosebud County, Montana is working on a schedule, even when you're not. Here's where you should be this July.
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Harvest corn as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Looking ahead to August
- First harvests: 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.
Forsyth, 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.
Forsyth Soil Profile
Soil Type
Loam
Soil pH
6.4-7.8
Drainage
Well Drained
Corn Planting Risk Windows
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.
Soil Compatibility in Forsyth
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (6.4–7.8) is more alkaline than Corn prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Rosebud County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Corn.
How to Plant Corn
Succession Planting Corn
Sow every 6.9 weeks. Last sowing by Jun 25 to harvest before frost.
Corn Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Corn
Corn needs approximately 1.5 inches of water per week (6.5" 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 | 6.5" | 2.9" | 3.6" | 🚿 Regular watering |
| Jun | 6.5" | 1.7" | 4.8" | 🚿 Regular watering |
| Jul | 6.5" | 2" | 4.5" | 🚿 Regular watering |
| Aug | 6.5" | 2.1" | 4.4" | 🚿 Regular watering |
| Sep | 6.5" | 1.7" | 4.8" | 🚿 Regular watering |
| Oct | 6.5" | 1.8" | 4.7" | 🚿 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 Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Corn Planting Timeline — Forsyth, 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
| Month | Activities |
|---|---|
| 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
1.5"/week · 2-3 times/week
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
145 days in Rosebud County
Growing Tips for Corn in Forsyth
Direct sow Corn outdoors after May 11 in Rosebud County when soil has warmed and frost danger has passed.
Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
Rosebud County receives only 23" of rain annually. Corn needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
When should I plant Corn in Forsyth, MT?
In Forsyth, 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 Forsyth, MT for Corn?
Forsyth sits in USDA Zone 4b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Corn grow in Forsyth's climate?
Yes — Corn grows well in Forsyth's temperate climate. Forsyth 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.