When should I plant tomatoes in ZIP 21201?

In ZIP 21201, the main tomatoes target is around Apr 22, based on the representative Baltimore frost station and USDA zone 7b.

When should I start tomatoes seeds indoors in 21201?

Start tomatoes seeds indoors in ZIP 21201 around Mar 4, about 42 days before the Apr 15 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 21201 planting calendar

When to plant tomatoes in Baltimore, MD - Zone 7b

Q: When is the first frost in Baltimore?

Baltimore (ZIP 21201) has an average first fall frost around Nov 5, leaving about 204 frost-free days.

In ZIP 21201, plant tomatoes around Apr 22; this uses the Baltimore frost station, USDA zone 7b, and tomatoes timing rules.

Your Baltimore calendar has a 204-day estimated frost-free season. This estimate uses the representative Baltimore frost station, USDA zone 7b, and tomatoes timing rules.

Source: baltimore-inner-harbor frost station, USDA zone 7b, 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 baltimore-inner-harbor frost station and USDA zone 7b, last updated 2026-06-28.

In the Baltimore area, gardeners usually wait until Apr 22 to set tomato transplants out because cold snaps near Apr 15 can still matter.

USDA zone 7b Baltimore frost station University of Maryland Extension Updated 2026-06-28

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Answer first

When to start tomatoes seeds indoors in Baltimore

In ZIP 21201, start tomatoes seeds indoors around Mar 4, about 42 days before the Apr 15 last-frost estimate.

Start tomatoes seeds indoors in Baltimore around Mar 4, about 42 days before the Apr 15 last-frost estimate.

Seed starting schedule

Tomatoes dates for Baltimore, MD

Step	Date	How to use it
Start Indoors	March 4, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	April 22, 2026	Move hardened-off seedlings outside after the frost-risk window.

Last frost

When is the last frost in Baltimore?

Baltimore (ZIP 21201) has an average last spring frost around Apr 15.

First frost

When is the first frost in Baltimore?

The average first fall frost is around Nov 5, giving about 204 frost-free days.

Season map

Tomatoes windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Start indoors

Mar 4

Transplant

Apr 22

Harvest

Jul 9

Frost watch

Aug 19

Reminder workflow

Every date has a next action

Start tomatoes indoorsMar 4

Last frost windowApr 15

Transplant tomatoesApr 22

First tomatoes harvest windowJul 9

Last tomatoes sowing targetAug 19

Signal	Value	Why it matters
Last frost estimate	April 15, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	November 5, 2026	Fall planting counts backward from this date.
Season length	204 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

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

University of Maryland 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 Nov 5. A conservative last sowing target is around Aug 19.