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When to plant Melon in Hamilton County County,

In Zone 5a (Hamilton County County), direct-sow Melon between May 8 and May 29 for spring, after the May 1 last-frost mark.

When to Plant Melon in Hamilton County, IA

Hamilton County, Iowa Zone 5a June

June in the garden — Hamilton County, Iowa

We've pulled the most time-sensitive tasks for Hamilton County, Iowa this June and put them front and centre. Tackle them in order.

Avg. last frost May 1
Avg. first frost October 7
Soil temp (4") 63°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Time to start melon inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

Looking ahead to July
  • First harvests: melon

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Melons are warm-season vine crops that produce sweet, juicy fruits in many varieties including muskmelon and honeydew. They need a long, hot growing season.

Hamilton County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 7, giving you a growing season of approximately 159 days.

At an elevation of 1,210 feet, Hamilton County receives approximately 35.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Melon to ensure they mature before fall.

Hamilton County, IA (Zone 5a) Moderate season
159 days
Last Spring Frost May 1
159 growing days
First Fall Frost October 7
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Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Melon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Mar 20 Transplant: May 8 🍅 Harvest: Jul 17 – Sep 4
Recommended (50%) ✓ Fits season (26 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Jul 24 – Sep 11
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Apr 9 Transplant: May 28 🍅 Harvest: Aug 6 – Sep 24

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 Hamilton County

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Melon's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Melon.

How to Plant Melon

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

Succession Planting Melon

2
successive plantings in your 159-day season

Sow every 8 weeks. Last sowing by Jun 29 to harvest before frost.

Melon Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 92 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Melon

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 Melon Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

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.

Melon needs ~850 GDD — county provides 1,590 GDD Excellent fit

Melon Planting Timeline — Hamilton County, IA

Melon Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 24 Jul 24 – Sep 11

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 Harvest
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

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

159 days in Hamilton County

Growing Tips for Melon in Hamilton County

Direct sow Melon outdoors after May 01 in Hamilton County when soil has warmed and frost danger has passed.

Common pests for 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 before transplanting. Plant on raised mounds of compost-enriched soil. Reduce watering as fruits ripen to concentrate sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Cucumber

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Melon in Hamilton County, IA?

Hamilton County is in Zone 5a with an average last frost of May 1. Plan your Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, IA?

Hamilton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 7.

When should I plant Melon in Hamilton County, ?

In Hamilton County, , plant Melon after the last frost (around May 1) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Hamilton County, for Melon?

Hamilton County sits in USDA Zone 5a. Melon grows reliably in zones 4a through 11b, so it's a good fit here.

Can Melon grow in Hamilton County's climate?

Yes — Melon grows well in Hamilton County's temperate climate. Hamilton County averages a 159-day frost-free season, with last frost around May 1 and first frost around October 7.

🌱

Your Hamilton County Garden Planner — Free

A 22-page printable planner built for Hamilton 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.

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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 Hamilton County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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