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When to Plant Winter Melon in Madison County, IA

Madison County, Iowa Zone 5b May

What to do in May

Your Madison 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 24
Avg. first frost October 11
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Get winter melon in the ground

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Plant winter melon from seed, right in the garden

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

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.

Madison County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 1,022 feet, Madison County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Winter Melon to ensure they mature before fall.

Madison County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11
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Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Feb 21 Transplant: May 2 🍅 Harvest: Aug 1 – Sep 19
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Feb 27 Transplant: May 8 🍅 Harvest: Aug 7 – Sep 25
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Aug 22 – Oct 10

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 Madison County

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

Soil pH

Your soil pH (6.3–6.9) is within Winter Melon's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

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 1.9" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 5.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 ~1,365 GDD — county provides 2,210 GDD Excellent fit

Winter Melon Planting Timeline — Madison County, IA

Winter Melon Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest August 7 Aug 7 – Sep 25

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
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 · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Madison County

Growing Tips for Winter Melon in Madison County

Direct sow Winter Melon outdoors after April 24 in Madison 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 Madison County, IA?

Madison County is in Zone 5b with an average last frost of April 24. Plan your Winter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, IA?

Madison County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.

🌱

Your Madison County Garden Planner — Free

A 24-page printable planner built for Madison 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 Madison 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.