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ZIP 78701 planting calendar

When to plant watermelon in Austin, TX - Zone 8b

In ZIP 78701, plant watermelon around Mar 19; this uses the Austin frost station, USDA zone 8b, and watermelon timing rules.

Your Austin calendar has a 260-day estimated frost-free season. This estimate uses the representative Austin frost station, USDA zone 8b, and watermelon timing rules.

Source: austin-bergstrom frost station, USDA zone 8b, 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 austin-bergstrom frost station and USDA zone 8b, last updated 2026-06-28.

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

USDA zone 8b Austin frost station Texas A&M AgriLife Extension Updated 2026-06-28
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Answer first

When to start watermelon seeds indoors in Austin

In ZIP 78701, start watermelon seeds indoors around Feb 12, about 21 days before the Mar 5 last-frost estimate.

Start watermelon seeds indoors in Austin around Feb 12, about 21 days before the Mar 5 last-frost estimate.

Seed starting schedule

Watermelon dates for Austin, TX

StepDateHow to use it
Start IndoorsFebruary 12, 2026Start seeds under lights or in a bright indoor seed-starting space.
Transplant OutdoorsMarch 19, 2026Move hardened-off seedlings outside after the frost-risk window.
Direct SowMarch 19, 2026Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Austin?

Austin (ZIP 78701) has an average last spring frost around Mar 5.

First frost

When is the first frost in Austin?

The average first fall frost is around Nov 20, giving about 260 frost-free days.

Season map

Watermelon windows by month

JanFebMarAprMayJunJulAugSepOctNovDec
Start indoors
Feb 12
Direct sow
Mar 19
Transplant
Mar 19
Harvest
Jun 17
Frost watch
Aug 22

Reminder workflow

Every date has a next action

Start watermelon indoorsFeb 12
Last frost windowMar 5
Direct sow watermelonMar 19
Transplant watermelonMar 19
First watermelon harvest windowJun 17
Last watermelon sowing targetAug 22
SignalValueWhy it matters
Last frost estimateMarch 5, 2026Warm-season transplant risk starts falling after this window.
First frost estimateNovember 20, 2026Fall planting counts backward from this date.
Season length260 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

Austin frost history and USDA zone 8b shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

Texas A&M AgriLife 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 Nov 20. A conservative last sowing target is around Aug 22.