When to Plant Sweet Corn in Silver Bow County, MT
Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.
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 Sweet Corn to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Sweet 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.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Sweet Corn Planting Timeline — Silver Bow County, MT
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | June 29 | Jun 29 – Jul 20 |
| Harvest | August 31 | Aug 31 – Oct 12 |
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
Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
USDA Zone
Zone 4a
Growing Season
84 days
Growing Tips for Silver Bow County
Plant in blocks of at least 4 rows for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Sweet Corn in Other Locations
Frequently Asked Questions
When should I plant Sweet Corn in Silver Bow County, MT?
Silver Bow County is in Zone 4a with an average last frost of June 15. Plan your Sweet 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.
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