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When to Plant Sunchoke in Jackson County, IA

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

Jackson County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 1,321 feet, Jackson County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Sunchoke during the growing season.

Jackson County, IA (Zone 5a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Transplant: Apr 25 🍅 Harvest: Aug 15 – Oct 10
Recommended (50%) ✓ Fits season (0 days to spare)
Transplant: May 1 🍅 Harvest: Aug 21 – Oct 16
Safe Start (90%) ✓ Fits season (1 days to spare)
Transplant: May 17 🍅 Harvest: Sep 6 – Nov 1

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 308 gal / 100 sq ft
Sunchoke needs ~1,788 GDD — county provides 2,502 GDD Excellent fit

Sunchoke Planting Timeline โ€” Jackson County, IA

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors May 1 May 1 โ€“ May 15
Harvest August 21 Aug 21 โ€“ Oct 16

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 Harvest
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 5a

Growing Season

182 days

Growing Tips for Jackson 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 Jackson County, IA?

Jackson County is in Zone 5a with an average last frost of April 17. Plan your Sunchoke planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, IA?

Jackson County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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