When should I plant lettuce in ZIP 46204?

In ZIP 46204, the main lettuce target is around Apr 11, based on the representative Indianapolis frost station and USDA zone 6b.

When should I start lettuce seeds indoors in 46204?

Start lettuce seeds indoors in ZIP 46204 around Mar 28, about 28 days before the Apr 25 last-frost estimate.

Is this a guaranteed planting date?

No. GrowZone uses frost-date estimates, hardiness zones, and crop timing rules for planning. Local microclimates and current weather can shift the right date.

ZIP 46204 planting calendar

When to plant lettuce in Indianapolis, IN - Zone 6b

Q: When is the first frost in Indianapolis?

Indianapolis (ZIP 46204) has an average first fall frost around Oct 15, leaving about 173 frost-free days.

In ZIP 46204, plant lettuce around Apr 11; this uses the Indianapolis frost station, USDA zone 6b, and lettuce timing rules.

Your Indianapolis calendar has a 173-day estimated frost-free season. This estimate uses the representative Indianapolis frost station, USDA zone 6b, and lettuce timing rules.

Source: indianapolis-intl frost station, USDA zone 6b, last updated 2026-06-28. Verify locally before planting high-value crops because microclimates, current weather, and yard exposure can move the safe date.

USDA zone 6b Indianapolis frost station Purdue Extension Updated 2026-06-28

Read the method

Answer first

When to start lettuce seeds indoors in Indianapolis

In ZIP 46204, start lettuce seeds indoors around Mar 28, about 28 days before the Apr 25 last-frost estimate.

Start lettuce seeds indoors in Indianapolis around Mar 28, about 28 days before the Apr 25 last-frost estimate.

Seed starting schedule

Lettuce dates for Indianapolis, IN

Step	Date	How to use it
Start Indoors	March 28, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	April 11, 2026	Move hardened-off seedlings outside after the frost-risk window.
Direct Sow	April 11, 2026	Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Indianapolis?

Indianapolis (ZIP 46204) has an average last spring frost around Apr 25.

First frost

When is the first frost in Indianapolis?

The average first fall frost is around Oct 15, giving about 173 frost-free days.

Season map

Lettuce windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Start indoors

Mar 28

Direct sow

Apr 11

Transplant

Apr 11

Harvest

Jun 5

Frost watch

Aug 21

Reminder workflow

Every date has a next action

Start lettuce indoorsMar 28

Direct sow lettuceApr 11

Transplant lettuceApr 11

Last frost windowApr 25

First lettuce harvest windowJun 5

Last lettuce sowing targetAug 21

Signal	Value	Why it matters
Last frost estimate	April 25, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	October 15, 2026	Fall planting counts backward from this date.
Season length	173 days	Longer seasons can support succession crops.
Spacing	8-12 in	Airflow and root space affect yield.
Soil temperature	40 F+	Seeds and transplants stall in cold soil.

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Local data

Why this date changes by ZIP

Indianapolis frost history and USDA zone 6b shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

Purdue 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

Lettuce timing notes

Succession sow every 10-14 days while weather is cool. Lettuce prefers sun to part shade, 8-12 in spacing, and soil near 40 F+.

For fall, count backward from Oct 15. A conservative last sowing target is around Aug 21.