When to Plant Corn in Adams County, ID
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.
Adams County, Idaho is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 25, giving you a growing season of approximately 128 days.
At an elevation of 6,593 feet, Adams County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Corn during the growing season.
Adams County Soil Profile
Soil Type
Loam
Soil pH
6.3-8
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
Corn Planting Timeline — Adams County, ID
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 27 | May 27 – Jun 17 |
| Harvest | July 29 | Jul 29 – Sep 23 |
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
Moderate — regular watering
Days to Maturity
60–100 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
128 days
Growing Tips for Adams 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
Level Up Your Garden
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Adams County, ID?
Adams County is in Zone 5a with an average last frost of May 20. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Adams County, ID?
Adams County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 25.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Adams County gardeners in Zone 5a 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.