When to Plant Corn in Grafton County, NH
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.
Grafton County, New Hampshire is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is October 7, giving you a growing season of approximately 148 days.
At an elevation of 524 feet, Grafton County receives approximately 44.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Corn to ensure they mature before fall.
Grafton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.3
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
Corn Planting Timeline — Grafton County, NH
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 26 | May 26 – Jun 16 |
| Harvest | July 28 | Jul 28 – Sep 22 |
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 4b
Growing Season
148 days
Growing Tips for Grafton 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 Grafton County, NH?
Grafton County is in Zone 4b with an average last frost of May 12. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grafton County, NH?
Grafton County, New Hampshire is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Grafton County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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