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ZIP 40202 planting calendar

When to plant watermelon in Louisville, KY - Zone 7a

In ZIP 40202, plant watermelon around Apr 29; this uses the Louisville frost station, USDA zone 7a, and watermelon timing rules.

Your Louisville calendar has a 193-day estimated frost-free season. This estimate uses the representative Louisville frost station, USDA zone 7a, and watermelon timing rules.

Source: louisville-intl frost station, USDA zone 7a, 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 louisville-intl frost station and USDA zone 7a, last updated 2026-06-28.

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

USDA zone 7a Louisville frost station University of Kentucky Cooperative Extension Updated 2026-06-28
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Answer first

When to start watermelon seeds indoors in Louisville

In ZIP 40202, start watermelon seeds indoors around Mar 25, about 21 days before the Apr 15 last-frost estimate.

Start watermelon seeds indoors in Louisville around Mar 25, about 21 days before the Apr 15 last-frost estimate.

Seed starting schedule

Watermelon dates for Louisville, KY

StepDateHow to use it
Start IndoorsMarch 25, 2026Start seeds under lights or in a bright indoor seed-starting space.
Transplant OutdoorsApril 29, 2026Move hardened-off seedlings outside after the frost-risk window.
Direct SowApril 29, 2026Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Louisville?

Louisville (ZIP 40202) has an average last spring frost around Apr 15.

First frost

When is the first frost in Louisville?

The average first fall frost is around Oct 25, giving about 193 frost-free days.

Season map

Watermelon windows by month

JanFebMarAprMayJunJulAugSepOctNovDec
Start indoors
Mar 25
Direct sow
Apr 29
Transplant
Apr 29
Harvest
Jul 28
Frost watch
Jul 27

Reminder workflow

Every date has a next action

Start watermelon indoorsMar 25
Last frost windowApr 15
Direct sow watermelonApr 29
Transplant watermelonApr 29
Last watermelon sowing targetJul 27
First watermelon harvest windowJul 28
SignalValueWhy it matters
Last frost estimateApril 15, 2026Warm-season transplant risk starts falling after this window.
First frost estimateOctober 25, 2026Fall planting counts backward from this date.
Season length193 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

Louisville frost history and USDA zone 7a shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

University of Kentucky Cooperative 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 25. A conservative last sowing target is around Jul 27.