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When to Plant Delicata Squash in Iowa County, WI

Iowa County, Wisconsin Zone 5a May

What to do in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 3
Avg. first frost October 7
Soil temp (4") 53°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Move delicata squash from tray to bed

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Outdoor sowing time: delicata squash

    These tolerate cool soil, so you're not gambling by sowing now.

Before June arrives, get these ready
  • Starting indoors: delicata squash

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Delicata squash is a winter squash with an edible skin and sweet, creamy orange flesh. Its compact vines make it suitable for smaller gardens.

Iowa County, Wisconsin is in USDA Zone 5a. 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 82°F, so choose short-season varieties of Delicata Squash to ensure they mature before fall.

Iowa County, WI (Zone 5a) 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 (25 days to spare)
Start indoors: Mar 23 Transplant: May 11 🍅 Harvest: Aug 3 – Sep 7
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Mar 29 Transplant: May 17 🍅 Harvest: Aug 9 – Sep 13
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Apr 16 Transplant: Jun 4 🍅 Harvest: Aug 27 – Oct 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.

Soil Compatibility in Iowa County

How your county's soil matches Delicata Squash's growing requirements.

Soil pH

Your soil pH (5.8–7.1) overlaps with Delicata Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Iowa County is excellent for Delicata Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Delicata Squash.

How to Plant Delicata Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Delicata Squash

2
successive plantings in your 157-day season

Sow every 9.1 weeks. Last sowing by Jun 29 to harvest before frost.

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

Monthly Watering Guide for Delicata Squash

Delicata Squash needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Delicata Squash Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Iowa County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Delicata Squash Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Delicata Squash needs ~1,035 GDD — county provides 1,805 GDD Excellent fit

Delicata Squash Planting Timeline — Iowa County, WI

Delicata Squash Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest August 9 Aug 9 – Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Iowa County

Growing Tips for Delicata Squash in Iowa County

Direct sow Delicata Squash outdoors after May 03 in Iowa County when soil has warmed and frost danger has passed.

Common pests for Delicata Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost on mounds. Harvest when skin is hard and ivory with green stripes. The thin skin does not need peeling. Stores 2-3 months in a cool place.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Iowa County is in Zone 5a with an average last frost of May 3. Plan your Delicata Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iowa County, WI?

Iowa County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 7.

🌱

Your Iowa County Garden Planner — Free

A 24-page printable planner built for Iowa County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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: May 2026.

Sources & credits

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