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When to Plant Watermelon in Renville County, MN

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.

Renville County, Minnesota is in USDA Zone 4a. The average last spring frost is April 30 and the first fall frost is October 6, giving you a growing season of approximately 159 days.

At an elevation of 758 feet, Renville County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Watermelon to ensure they mature before fall.

Renville County, MN (Zone 4a) Moderate season
159 days
Last Spring Frost April 30
159 growing days
First Fall Frost October 6

Renville County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Mar 13 Transplant: May 15 🍅 Harvest: Jul 24 – Sep 11
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Jul 30 – Sep 17
Safe Start (90%) ✓ Fits season (13 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 Renville County

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

Soil pH

Your soil pH (6.0โ€“7.2) is within Watermelon's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Renville County is excellent for Watermelon โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Watermelon.

How to Plant Watermelon

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

Succession Planting Watermelon

2
successive plantings in your 159-day season

Sow every 8 weeks. Last sowing by Jun 28 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 848 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 โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 2.2" 0" โ„๏ธ Dormant
Apr 6.5" 3" 3.5" ๐Ÿšฟ Regular watering
May 6.5" 4.4" 2.1" ๐Ÿ’ง Light watering
Jun 6.5" 4.7" 1.8" ๐Ÿ’ง Light watering
Jul 6.5" 4.1" 2.4" ๐Ÿ’ง Light watering
Aug 6.5" 3.5" 3" ๐Ÿ’ง Light watering
Sep 6.5" 2.5" 4" ๐Ÿšฟ Regular watering
Oct 6.5" 2.5" 4" ๐Ÿšฟ Regular watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Renville County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~914 GDD — county provides 1,709 GDD Excellent fit

Watermelon Planting Timeline โ€” Renville County, MN

Watermelon Planting Calendar

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

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

159 days in Renville County

Growing Tips for Watermelon in Renville County

Direct sow Watermelon outdoors after April 30 in Renville 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 Renville 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 Renville County, MN?

Renville County is in Zone 4a with an average last frost of April 30. Plan your Watermelon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Renville County, MN?

Renville County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is April 30 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Renville County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Renville County, MN. Local conditions may vary. Last updated: April 2026.