When should I plant spinach in ZIP 02108?

In ZIP 02108, the main spinach target is around Mar 23, based on the representative Boston frost station and USDA zone 7a.

When should I start spinach seeds indoors in 02108?

Spinach is usually direct-sown for ZIP 02108. Use the Mar 23 planting window instead of starting it indoors.

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 02108 planting calendar

When to plant spinach in Boston, MA - Zone 7a

Q: When is the first frost in Boston?

Boston (ZIP 02108) has an average first fall frost around Oct 31, leaving about 194 frost-free days.

In ZIP 02108, plant spinach around Mar 23; this uses the Boston frost station, USDA zone 7a, and spinach timing rules.

Your Boston calendar has a 194-day estimated frost-free season. This estimate uses the representative Boston frost station, USDA zone 7a, and spinach timing rules.

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

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

USDA zone 7a Boston frost station UMass Extension Updated 2026-06-28

Read the method

Answer first

When to start spinach seeds indoors in Boston

In ZIP 02108, spinach is usually direct-sown around Mar 23 instead of started indoors.

Spinach is normally direct-sown in Boston. Use around Mar 23 as the outdoor planting window for ZIP 02108.

Seed starting schedule

Spinach dates for Boston, MA

Step	Date	How to use it
Direct Sow	March 23, 2026	Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Boston?

Boston (ZIP 02108) has an average last spring frost around Apr 20.

First frost

When is the first frost in Boston?

The average first fall frost is around Oct 31, giving about 194 frost-free days.

Season map

Spinach windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Direct sow

Mar 23

Harvest

May 7

Frost watch

Sep 16

Reminder workflow

Every date has a next action

Direct sow spinachMar 23

Last frost windowApr 20

First spinach harvest windowMay 7

Last spinach sowing targetSep 16

Signal	Value	Why it matters
Last frost estimate	April 20, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	October 31, 2026	Fall planting counts backward from this date.
Season length	194 days	Longer seasons can support succession crops.
Spacing	4-6 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

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

UMass 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

Spinach timing notes

Plant early and again in late summer for fall leaves. Spinach prefers sun to part shade, 4-6 in spacing, and soil near 40 F+.

For fall, count backward from Oct 31. A conservative last sowing target is around Sep 16.