When to Plant Sunchoke in Iron County, MI
Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.
Iron County, Michigan is in USDA Zone 4a. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.
At an elevation of 531 feet, Iron County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Sunchoke to ensure they mature before fall.
Iron County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
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 6/10 — consider drought-tolerant varieties and mulching
Sunchoke Planting Timeline — Iron County, MI
Sunchoke Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 9 | Jun 9 – Jun 23 |
| Harvest | September 29 | Sep 29 – Nov 3 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
110–150 days
Soil pH
6 – 7.5
USDA Zone
Zone 4a
Growing Season
118 days
Growing Tips for Iron County
Plant tubers 4 inches deep in early spring. Contain plants with barriers as they spread aggressively. Harvest after frost or leave in ground and dig as needed through winter.
Companion Planting
Good Companions
Level Up Your Garden
Sunchoke in Other Locations
Frequently Asked Questions
When should I plant Sunchoke in Iron County, MI?
Iron County is in Zone 4a with an average last frost of May 26. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iron County, MI?
Iron County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 26 and first fall frost is September 21.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Iron County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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