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When to Plant Crookneck Squash in Cass County, IA

Cass County, Iowa Zone 5b May

May in Cass County, Iowa — your action list

Your Cass County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 25
Avg. first frost October 9
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Move crookneck squash from tray to bed

    Your last frost (April 25) has passed. These warm-season crops can handle outdoor soil now.

  2. Put crookneck squash seeds straight in the ground

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

  3. Begin indoor sowing: crookneck squash

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

A few tasks this May that'll pay off in June
  • First harvests: crookneck squash

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Yellow crookneck squash is a summer squash with a curved neck and bumpy, bright yellow skin. It has a buttery flavor and is best harvested young when 4-6 inches long.

Cass County, Iowa is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 9, giving you a growing season of approximately 167 days.

At an elevation of 1,043 feet, Cass County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Crookneck Squash during the growing season.

Cass County, IA (Zone 5b) Moderate season
167 days
Last Spring Frost April 25
167 growing days
First Fall Frost October 9

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Mar 16 Transplant: May 4 🍅 Harvest: Jun 22 – Jul 20
Recommended (50%) ✓ Fits season (76 days to spare)
Start indoors: Mar 21 Transplant: May 9 🍅 Harvest: Jun 27 – Jul 25
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Apr 7 Transplant: May 26 🍅 Harvest: Jul 14 – Aug 11

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 Cass County

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

Soil pH

Your soil pH (6.2–6.7) is within Crookneck Squash's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Crookneck Squash will thrive.

How to Plant Crookneck Squash

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

Succession Planting Crookneck Squash

4
successive plantings in your 167-day season

Sow every 5.1 weeks. Last sowing by Aug 10 to harvest before frost.

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 324 gal / 100 sq ft

Monthly Watering Guide for Crookneck Squash

Crookneck 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 Crookneck Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.4" 0.9" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Crookneck 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.

Crookneck Squash needs ~761 GDD — county provides 2,421 GDD Excellent fit

Crookneck Squash Planting Timeline — Cass County, IA

Crookneck Squash Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest June 27 Jun 27 – Jul 25

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 Harvest
July Harvest
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

167 days in Cass County

Growing Tips for Crookneck Squash in Cass County

Direct sow Crookneck Squash outdoors after April 25 in Cass County when soil has warmed and frost danger has passed.

Your generous 167.0-day season in Cass County allows multiple plantings of Crookneck Squash. Sow every 22.0 days for continuous harvest.

Common pests for Crookneck 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. Pick frequently while small for tender texture. Skin becomes tough and warty on larger fruits. Very productive 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 Crookneck Squash in Cass County, IA?

Cass County is in Zone 5b with an average last frost of April 25. Plan your Crookneck Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, IA?

Cass County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 9.

🌱

Your Cass County Garden Planner — Free

A 24-page printable planner built for Cass 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 Cass 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.