Blog

When to plant Watermelon in Douglas County, MN

Douglas County sits in USDA Zone 4b. Plant Watermelon between May 17 (after last frost on May 3) and June 7.

When to Plant Watermelon in Douglas County, MN

Watermelon

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.

Douglas County, Minnesota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 4, giving you a growing season of approximately 154 days.

At an elevation of 1,010 feet, Douglas County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Watermelon to ensure they mature before fall.

Douglas County, MN (Zone 4b) Moderate season
154 days
Last Spring Frost May 3
154 growing days
First Fall Frost October 4

Douglas County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Watermelon to Grow

15-20 lbs
Average yield per plant
1
Plants per person
2 sq ft
Space per person

For a family of 4, plant approximately 4 watermelon plants in about 8 sq ft. In Douglas County's 154-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Watermelon Planting Timeline — Douglas County, MN

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest August 2 Aug 2 – Sep 20

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
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 4b

📆 Growing Season

154 days in Douglas County

Growing Tips for Douglas 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Douglas County, MN?

Douglas County is in Zone 4b with an average last frost of May 3. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, MN?

Douglas County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 4.

When should I plant Watermelon in Douglas County, MN?

In Douglas County, MN, plant Watermelon after the last frost (around May 3) and before the first frost (around October 4). Best results when soil holds above 50°F.

What growing zone is Douglas County, MN for Watermelon?

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

Can Watermelon grow in Douglas County's climate?

Yes — Watermelon grows well in Douglas County's temperate climate. Douglas County averages a 154-day frost-free season, with last frost around May 3 and first frost around October 4.

🌱

Your Douglas County Garden Planner — Free

A 22-page printable planner built for Douglas 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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