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When to Plant Watermelon in Yellow Medicine County, MN

Yellow Medicine County, Minnesota Zone 4b May

Yellow Medicine County, Minnesota gardeners: here's your May plan

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

Avg. last frost April 30
Avg. first frost October 4
Soil temp (4") 52°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Set out watermelon seedlings

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Put watermelon seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

A few tasks this May that'll pay off in June
  • Starting indoors: watermelon

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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.

Yellow Medicine County, Minnesota is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 4, giving you a growing season of approximately 157 days.

At an elevation of 1,382 feet, Yellow Medicine County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Watermelon to ensure they mature before fall.

Yellow Medicine County, MN (Zone 4b) Moderate season
157 days
Last Spring Frost April 30
157 growing days
First Fall Frost October 4
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Yellow Medicine County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Jul 30 – Sep 17
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Aug 14 – Oct 2

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 Yellow Medicine County

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

Soil pH

Your soil pH (6.2–6.8) is within Watermelon's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Watermelon.

Organic Matter

Organic matter is excellent (4.3%) — Watermelon will thrive.

How to Plant Watermelon

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

Succession Planting Watermelon

2
successive plantings in your 157-day season

Sow every 8 weeks. Last sowing by Jun 26 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 1,745 gal / 100 sq ft
Drought risk

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

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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 6.5" 3" 3.5" 🚿 Regular watering
May 6.5" 3.7" 2.8" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 4.4" 2.1" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 2.5" 4" 🚿 Regular watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Yellow Medicine 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 ~978 GDD — county provides 1,805 GDD Excellent fit

Watermelon Planting Timeline — Yellow Medicine County, MN

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 14 May 14 – Jun 4
Harvest July 30 Jul 30 – Sep 17

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 Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

157 days in Yellow Medicine County

Growing Tips for Watermelon in Yellow Medicine County

Direct sow Watermelon outdoors after April 30 in Yellow Medicine 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.

Recommended Watermelon Varieties for Yellow Medicine County

Compact, early melons for shorter seasons

Sugar Baby (75d) Blacktail Mountain (70d) Golden Midget (70d)

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 Yellow Medicine County, MN?

Yellow Medicine County is in Zone 4b with an average last frost of April 30. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yellow Medicine County, MN?

Yellow Medicine County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 4.

🌱

Your Yellow Medicine County Garden Planner — Free

A 24-page printable planner built for Yellow Medicine County (Zone 4b). 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 Yellow Medicine County, MN. 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.