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When to Plant Patty Pan Squash in Jefferson County, IA

Jefferson County, Iowa Zone 5b May

What to do in May

May is a pivotal month for Jefferson County, Iowa gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 21
Avg. first frost October 14
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Transplant patty pan squash outside

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Fire up the seed-starting tray: patty pan squash

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Looking ahead to June
  • First harvests: patty pan squash

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Patty pan squash is a summer squash with a distinctive flying-saucer shape and scalloped edges. It comes in white, yellow, and green varieties with a mild, nutty flavor.

Jefferson County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.

At an elevation of 1,279 feet, Jefferson County receives approximately 37.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Patty Pan Squash to ensure they mature before fall.

Jefferson County, IA (Zone 5b) Moderate season
176 days
Last Spring Frost April 21
176 growing days
First Fall Frost October 14
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jun 16 – Jul 14
Recommended (50%) ✓ Fits season (85 days to spare)
Start indoors: Mar 17 Transplant: May 5 🍅 Harvest: Jun 23 – Jul 21
Safe Start (90%) ✓ Fits season (86 days to spare)
Start indoors: Mar 30 Transplant: May 18 🍅 Harvest: Jul 6 – Aug 3

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 Jefferson County

How your county's soil matches Patty Pan Squash's growing requirements.

Soil pH

Your soil pH (6.0–7.2) is within Patty Pan Squash's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Patty Pan Squash.

Organic Matter

Organic matter is excellent (4.5%) — Patty Pan Squash will thrive.

How to Plant Patty Pan Squash

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

Succession Planting Patty Pan Squash

4
successive plantings in your 176-day season

Sow every 5.1 weeks. Last sowing by Aug 15 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 744 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Patty Pan Squash

Patty Pan 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 Patty Pan Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

Patty Pan 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.

Patty Pan Squash needs ~643 GDD — county provides 2,156 GDD Excellent fit

Patty Pan Squash Planting Timeline — Jefferson County, IA

Patty Pan Squash Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 5 May 5 – May 19
Direct Sow April 28 Apr 28 – May 19
Harvest June 23 Jun 23 – Jul 21

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Jefferson County

Growing Tips for Patty Pan Squash in Jefferson County

Direct sow Patty Pan Squash outdoors after April 21 in Jefferson County when soil has warmed and frost danger has passed.

Your generous 176.0-day season in Jefferson County allows multiple plantings of Patty Pan Squash. Sow every 22.0 days for continuous harvest.

Common pests for Patty Pan 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. Harvest when 2-4 inches across for best texture and flavor. Larger fruits become seedy and tough. Very prolific producers in warm weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Patty Pan Squash in Jefferson County, IA?

Jefferson County is in Zone 5b with an average last frost of April 21. Plan your Patty Pan Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, IA?

Jefferson County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 14.

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Your Jefferson County Garden Planner — Free

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

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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 Jefferson County, IA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.