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When to Plant Watermelon in Cape Girardeau County, MO

Cape Girardeau County, Missouri Zone 7a May

Top priorities for Cape Girardeau County, Missouri gardeners in May

Your garden in Cape Girardeau County, Missouri is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 10
Avg. first frost October 21
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14 hrs
  1. Indoor seed-starting week for watermelon

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

Cape Girardeau County, Missouri is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 21, giving you a growing season of approximately 194 days.

At an elevation of 880 feet, Cape Girardeau County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Watermelon during the growing season.

Cape Girardeau County, MO (Zone 7a) Moderate season
194 days
Last Spring Frost April 10
194 growing days
First Fall Frost October 21

Cape Girardeau County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 8 Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 16
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🍅 Harvest: Jul 3 – Aug 21
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Jul 17 – Sep 4

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 Cape Girardeau County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Watermelon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Watermelon.

How to Plant Watermelon

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

Succession Planting Watermelon

3
successive plantings in your 194-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,169 gal / 100 sq ft

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 6.5" 3.9" 2.6" 💧 Light watering
May 6.5" 4.9" 1.6" 💧 Light watering
Jun 6.5" 4.7" 1.8" 💧 Light watering
Jul 6.5" 4.7" 1.8" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 3" 3.5" 🚿 Regular watering
Oct 6.5" 2.9" 3.6" 🚿 Regular watering
Nov 2.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Watermelon 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.

Watermelon needs ~1,424 GDD — county provides 3,249 GDD Excellent fit

Watermelon Planting Timeline — Cape Girardeau County, MO

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest July 3 Jul 3 – Aug 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in Cape Girardeau County

Growing Tips for Watermelon in Cape Girardeau County

Direct sow Watermelon outdoors after April 10 in Cape Girardeau County when soil has warmed and frost danger has passed.

Common pests for Watermelon 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 or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Cape Girardeau County, MO?

Cape Girardeau County is in Zone 7a with an average last frost of April 10. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cape Girardeau County, MO?

Cape Girardeau County, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 21.

🌱

Your Cape Girardeau County Garden Planner — Free

A 24-page printable planner built for Cape Girardeau County (Zone 7a). 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 Cape Girardeau County, MO. 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.