Warm-Season Vegetable

When to Plant Watermelon in Minnesota

The ultimate summer treat. Watermelons need heat, space, and patience — but the payoff is pure joy.

The Short Answer

In Minnesota, watermelon planting dates vary by region. In Northern Minnesota, your average last frost is around May 15 - Jun 1, while Southern Minnesota sees its last frost around Apr 25 - May 10. Since watermelon are frost-sensitive, start seeds indoors 3 weeks before your last frost, then transplant outside 2 weeks after frost danger has passed. Rich prairie soils in south and west. Rocky and thin soils in north. Generally excellent for gardening in southern half.

Minnesota Frost Dates

Your planting dates depend on which part of Minnesota you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Northern Minnesota 3a, 3b May 15 - Jun 1 Sep 5 - Sep 20
Central Minnesota 3b, 4a May 5 - May 20 Sep 15 - Oct 1
Southern Minnesota 4a, 4b Apr 25 - May 10 Sep 25 - Oct 10

Watermelon Planting Schedule for Minnesota

Northern Minnesota (Zones 3a, 3b)

Average last frost: May 15 - Jun 1 · Average first frost: Sep 5 - Sep 20

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
3 wks after frost

Central Minnesota (Zones 3b, 4a)

Average last frost: May 5 - May 20 · Average first frost: Sep 15 - Oct 1

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
3 wks after frost

Southern Minnesota (Zones 4a, 4b)

Average last frost: Apr 25 - May 10 · Average first frost: Sep 25 - Oct 10

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
3 wks after frost

Growing Watermelon in Minnesota

Watermelon in Minnesota's Climate

Watermelon pushes the limits of cold-climate gardening. Choose short-season varieties only — Sugar Baby (75 days), Blacktail Mountain (75 days, bred for northern conditions). Start indoors 3 weeks before last frost. Black plastic mulch and row cover are essential. Expect smaller fruits than southern growers — but a sun-warmed watermelon from your own cold-climate garden is incomparably satisfying.

Soil Considerations for Minnesota

Rich prairie soils in south and west. Rocky and thin soils in north. Generally excellent for gardening in southern half. Make sure soil has warmed to at least 70°F before planting watermelon outside.

Minnesota Climate & Growing Season

Long, cold winters. Warm summers. Short but productive growing season with long summer days. Hardy varieties essential. Watermelon cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.

Growing season length varies across Minnesota: Northern Minnesota (3a, 3b) has a last frost around May 15 - Jun 1, while Southern Minnesota (4a, 4b) sees frost end around Apr 25 - May 10. This difference matters for watermelon — transplant timing shifts by several weeks across the state.

Growing Tips

Black plastic mulch warms soil faster. Check ripeness by looking for a yellow ground spot and listening for a hollow thump.

Companion Planting

Plant watermelon alongside these companions for better growth:

Corn Sunflowers Marigolds

Keep watermelon away from:

Potatoes

The Bottom Line

Watermelon can be grown successfully across Minnesota, but your exact planting dates depend on which region you're in. Northern Minnesota gardeners should plan around a May 15 - Jun 1 last frost, while those in Southern Minnesota can typically plant earlier. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Watermelon Growing Guide National planting guide with all states Minnesota Planting Calendar All plants for Minnesota Watermelon in Alabama Alabama planting dates Watermelon in Alaska Alaska planting dates Watermelon in Arizona Arizona planting dates Watermelon in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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