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ZIP 55401 planting calendar

When to plant watermelon in Minneapolis, MN - Zone 5a

In ZIP 55401, plant watermelon around May 24; this uses the Minneapolis frost station, USDA zone 5a, and watermelon timing rules.

Your Minneapolis calendar has a 144-day estimated frost-free season. This estimate uses the representative Minneapolis frost station, USDA zone 5a, and watermelon timing rules.

Source: minneapolis-st-paul frost station, USDA zone 5a, last updated 2026-06-28. Verify locally before planting high-value crops because microclimates, current weather, and yard exposure can move the safe date.

Reviewed by GrowZone Editorial. Calculated from the minneapolis-st-paul frost station and USDA zone 5a, last updated 2026-06-28.

In the Minneapolis area, watermelon timing follows the Minneapolis frost window, so the local ZIP date can differ from a broad zone-only calendar.

USDA zone 5a Minneapolis frost station University of Minnesota Extension Updated 2026-06-28
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Answer first

When to start watermelon seeds indoors in Minneapolis

In ZIP 55401, start watermelon seeds indoors around Apr 19, about 21 days before the May 10 last-frost estimate.

Start watermelon seeds indoors in Minneapolis around Apr 19, about 21 days before the May 10 last-frost estimate.

Seed starting schedule

Watermelon dates for Minneapolis, MN

StepDateHow to use it
Start IndoorsApril 19, 2026Start seeds under lights or in a bright indoor seed-starting space.
Transplant OutdoorsMay 24, 2026Move hardened-off seedlings outside after the frost-risk window.
Direct SowMay 24, 2026Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Minneapolis?

Minneapolis (ZIP 55401) has an average last spring frost around May 10.

First frost

When is the first frost in Minneapolis?

The average first fall frost is around Oct 1, giving about 144 frost-free days.

Season map

Watermelon windows by month

JanFebMarAprMayJunJulAugSepOctNovDec
Start indoors
Apr 19
Direct sow
May 24
Transplant
May 24
Harvest
Aug 22
Frost watch
Jul 3

Reminder workflow

Every date has a next action

Start watermelon indoorsApr 19
Last frost windowMay 10
Direct sow watermelonMay 24
Transplant watermelonMay 24
Last watermelon sowing targetJul 3
First watermelon harvest windowAug 22
SignalValueWhy it matters
Last frost estimateMay 10, 2026Warm-season transplant risk starts falling after this window.
First frost estimateOctober 1, 2026Fall planting counts backward from this date.
Season length144 daysLonger seasons can support succession crops.
Spacing36-60 inAirflow and root space affect yield.
Soil temperature70 F+Seeds and transplants stall in cold soil.

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Local data

Why this date changes by ZIP

Minneapolis frost history and USDA zone 5a shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

University of Minnesota Extension is the kind of local source to verify against when a crop is expensive, weather is unusual, or your yard has a cold pocket.

Crop note

Watermelon timing notes

Wait for warm soil; watermelon stalls when nights stay cool. Watermelon prefers full sun, 36-60 in spacing, and soil near 70 F+.

For fall, count backward from Oct 1. A conservative last sowing target is around Jul 3.