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When to Plant Sunchoke in Winnebago County, WI

Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.

Winnebago County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 608 feet, Winnebago County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Sunchoke to ensure they mature before fall.

Winnebago County, WI (Zone 4b) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Winnebago County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 9 🍅 Harvest: Aug 29 – Oct 3
Recommended (50%) ✓ Fits season (4 days to spare)
Transplant: May 14 🍅 Harvest: Sep 3 – Oct 8
Safe Start (90%) ✓ Fits season (4 days to spare)
Transplant: May 29 🍅 Harvest: Sep 18 – Oct 23

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

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 26 gal / 100 sq ft
Sunchoke needs ~1,495 GDD — county provides 1,897 GDD Good fit

Sunchoke Planting Timeline โ€” Winnebago County, WI

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 โ€“ May 28
Harvest September 3 Sep 3 โ€“ Oct 8

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July โ€”
August โ€”
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

110โ€“150 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

165 days

Growing Tips for Winnebago 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

Frequently Asked Questions

When should I plant Sunchoke in Winnebago County, WI?

Winnebago County is in Zone 4b with an average last frost of April 30. Plan your Sunchoke planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Winnebago County, WI?

Winnebago County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Winnebago County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Winnebago County, WI. Local conditions may vary. Last updated: April 2026.