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When to Plant Winter Melon in Henry County, IA

Henry County, Iowa Zone 5b May

Your May game plan for Henry County, Iowa

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Henry County, Iowa.

Avg. last frost April 21
Avg. first frost October 14
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Move winter melon into the garden

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

To set up a strong June, finish these tasks
  • Starting indoors: winter melon

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Winter melon (wax gourd) is a large Asian squash with a waxy white coating that allows long storage. The mild flesh is used in soups and stir-fries.

Henry 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 879 feet, Henry County receives approximately 40.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Winter Melon during the growing season.

Henry 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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Henry County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Feb 17 Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 15
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Aug 4 – Sep 22
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Mar 9 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 5

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 Henry County

How your county's soil matches Winter Melon's growing requirements.

Soil pH

Your soil pH (5.8–7.2) overlaps with Winter Melon's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Henry County is excellent for Winter Melon — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Winter Melon will thrive.

How to Plant Winter Melon

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

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 64 gal / 100 sq ft

Monthly Watering Guide for Winter Melon

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

Month Winter Melon Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 4.9" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Winter Melon 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.

Winter Melon needs ~1,522 GDD — county provides 2,552 GDD Excellent fit

Winter Melon Planting Timeline — Henry County, IA

Winter Melon Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors May 5 May 5 – May 19
Direct Sow April 28 Apr 28 – May 19
Harvest August 4 Aug 4 – Sep 22

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Henry County

Growing Tips for Winter Melon in Henry County

Direct sow Winter Melon outdoors after April 21 in Henry County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 3-4 weeks early. Provide ample space for sprawling vines. Harvest when the waxy coating develops on the rind. Fruits can weigh 15-30 pounds.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Winter Melon in Henry County, IA?

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

What planting zone is Henry County, IA?

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

🌱

Your Henry County Garden Planner — Free

A 24-page printable planner built for Henry 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 Henry 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.