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When to Plant Watermelon in Waushara County, WI

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.

Waushara County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.

At an elevation of 560 feet, Waushara County receives approximately 37.4 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.

Waushara County, WI (Zone 4b) Moderate season
162 days
Last Spring Frost April 30
162 growing days
First Fall Frost October 9

Waushara County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Jul 30 – Sep 17
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Apr 6 Transplant: Jun 8 🍅 Harvest: Aug 17 – Oct 5

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 44 gal / 100 sq ft
Watermelon needs ~914 GDD — county provides 1,741 GDD Excellent fit

Watermelon Planting Timeline โ€” Waushara County, WI

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

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

162 days

Growing Tips for Waushara County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Watermelon in Waushara County, WI?

Waushara County is in Zone 4b 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 Waushara County, WI?

Waushara County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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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 Waushara County, WI. Local conditions may vary. Last updated: April 2026.