When should I plant tomatoes in ZIP 60601?

In ZIP 60601, the main tomatoes target is around May 2, based on the representative Chicago frost station and USDA zone 6a.

When should I start tomatoes seeds indoors in 60601?

Start tomatoes seeds indoors in ZIP 60601 around Mar 14, about 42 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 60601 planting calendar

When to plant tomatoes in Chicago, IL - Zone 6a

Q: When is the first frost in Chicago?

Chicago (ZIP 60601) has an average first fall frost around Oct 20, leaving about 178 frost-free days.

In ZIP 60601, plant tomatoes around May 2; this uses the Chicago frost station, USDA zone 6a, and tomatoes timing rules.

Your Chicago calendar has a 178-day estimated frost-free season. This estimate uses the representative Chicago frost station, USDA zone 6a, and tomatoes timing rules.

Source: chicago-ohare frost station, USDA zone 6a, 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 chicago-ohare frost station and USDA zone 6a, last updated 2026-06-28.

In the Chicago area, gardeners usually wait until May 2 to set tomato transplants out because cold snaps near Apr 25 can still matter.

USDA zone 6a Chicago frost station University of Illinois Extension Updated 2026-06-28

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Answer first

When to start tomatoes seeds indoors in Chicago

In ZIP 60601, start tomatoes seeds indoors around Mar 14, about 42 days before the Apr 25 last-frost estimate.

Start tomatoes seeds indoors in Chicago around Mar 14, about 42 days before the Apr 25 last-frost estimate.

Seed starting schedule

Tomatoes dates for Chicago, IL

Step	Date	How to use it
Start Indoors	March 14, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	May 2, 2026	Move hardened-off seedlings outside after the frost-risk window.

Last frost

When is the last frost in Chicago?

Chicago (ZIP 60601) has an average last spring frost around Apr 25.

First frost

When is the first frost in Chicago?

The average first fall frost is around Oct 20, giving about 178 frost-free days.

Season map

Tomatoes windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Start indoors

Mar 14

Transplant

May 2

Harvest

Jul 19

Frost watch

Aug 3

Reminder workflow

Every date has a next action

Start tomatoes indoorsMar 14

Last frost windowApr 25

Transplant tomatoesMay 2

First tomatoes harvest windowJul 19

Last tomatoes sowing targetAug 3

Signal	Value	Why it matters
Last frost estimate	April 25, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	October 20, 2026	Fall planting counts backward from this date.
Season length	178 days	Longer seasons can support succession crops.
Spacing	18-24 in	Airflow and root space affect yield.
Soil temperature	60 F+	Seeds and transplants stall in cold soil.

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Local data

Why this date changes by ZIP

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

University of Illinois 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

Tomatoes timing notes

Harden seedlings off for a week before transplanting. Tomatoes prefers full sun, 18-24 in spacing, and soil near 60 F+.

For fall, count backward from Oct 20. A conservative last sowing target is around Aug 3.