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When to Plant Spaghetti Squash in Iowa County, WI

Spaghetti squash is a winter squash whose cooked flesh separates into pasta-like strands. It is a popular low-carb alternative to pasta.

Iowa County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.

At an elevation of 602 feet, Iowa County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Spaghetti Squash to ensure they mature before fall.

Iowa County, WI (Zone 4b) Moderate season
157 days
Last Spring Frost May 3
157 growing days
First Fall Frost October 7

Iowa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Aug 17 – Sep 14
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 22 Transplant: May 24 🍅 Harvest: Aug 23 – Sep 20
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Sep 10 – Oct 8

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 55 gal / 100 sq ft
Spaghetti Squash needs ~1,064 GDD — county provides 1,805 GDD Excellent fit

Spaghetti Squash Planting Timeline โ€” Iowa County, WI

Spaghetti Squash Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 โ€“ Apr 5
Transplant Outdoors May 24 May 24 โ€“ Jun 7
Direct Sow May 17 May 17 โ€“ Jun 7
Harvest August 23 Aug 23 โ€“ Sep 20

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

157 days

Growing Tips for Iowa County

Direct sow on mounds after last frost. Harvest when skin turns golden yellow and is hard. Store in a cool, dry place for 2-3 months. Bake or microwave halves until tender.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Spaghetti Squash in Iowa County, WI?

Iowa County is in Zone 4b with an average last frost of May 3. Plan your Spaghetti Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Iowa County, WI?

Iowa County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Iowa County gardeners in Zone 4b 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 Iowa County, WI. Local conditions may vary. Last updated: April 2026.