When to Plant Corn in Silver Bow County, MT
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.
Silver Bow County, Montana is in USDA Zone 4a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.
At an elevation of 5,305 feet, Silver Bow County receives approximately 14.3 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. With low rainfall, drip irrigation is essential for growing Corn successfully. Mulch heavily to conserve soil moisture.
Silver Bow County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.3
Drainage
Well Drained
Plant 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 Silver Bow County
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (6.6–8.3) is more alkaline than Corn prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Silver Bow County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Corn.
How to Plant Corn
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 180 sq ft. In Silver Bow County's 84-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Plant Water Budget
Water stress score is 8/10 — 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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 1.4" | 0" | ❄️ Dormant |
| May | — | 1.5" | 0" | ❄️ Dormant |
| Jun | 6.5" | 0.9" | 5.6" | 🚿 Regular watering |
| Jul | 6.5" | 1.1" | 5.4" | 🚿 Regular watering |
| Aug | 6.5" | 1.8" | 4.7" | 🚿 Regular watering |
| Sep | 6.5" | 1.1" | 5.4" | 🚿 Regular watering |
| Oct | — | 1.1" | 0" | ❄️ Dormant |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Silver Bow 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 — Silver Bow County, MT
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | June 29 | Jun 29 – Jul 20 |
| Harvest | August 31 | Aug 31 – Oct 26 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Direct Sow |
| July | Direct Sow |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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 4a
📆 Growing Season
84 days in Silver Bow County
Growing Tips for Corn in Silver Bow County
Direct sow Corn outdoors after June 15 in Silver Bow County when soil has warmed and frost danger has passed.
Your 84.0-day growing season in Silver Bow County is tight for Corn (60.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
Silver Bow County receives only 14" 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.
Recommended Corn Varieties for Silver Bow County
Ultra-early corn varieties for your season
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Silver Bow County, MT?
Silver Bow County is in Zone 4a with an average last frost of June 15. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Silver Bow County, MT?
Silver Bow County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is June 15 and first fall frost is September 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Silver Bow County gardeners in Zone 4a 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.