When should I plant radishes in ZIP 97204?

In ZIP 97204, the main radishes target is around Mar 4, based on the representative Portland frost station and USDA zone 9a.

When should I start radishes seeds indoors in 97204?

Radishes is usually direct-sown for ZIP 97204. Use the Mar 4 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 97204 planting calendar

When to plant radishes in Portland, OR - Zone 9a

Q: When is the first frost in Portland?

Portland (ZIP 97204) has an average first fall frost around Nov 10, leaving about 223 frost-free days.

In ZIP 97204, plant radishes around Mar 4; this uses the Portland frost station, USDA zone 9a, and radishes timing rules.

Your Portland calendar has a 223-day estimated frost-free season. This estimate uses the representative Portland frost station, USDA zone 9a, and radishes timing rules.

Source: portland-intl frost station, USDA zone 9a, 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 9a Portland frost station Oregon State University Extension Updated 2026-06-28

Read the method

Answer first

When to start radishes seeds indoors in Portland

In ZIP 97204, radishes is usually direct-sown around Mar 4 instead of started indoors.

Radishes is normally direct-sown in Portland. Use around Mar 4 as the outdoor planting window for ZIP 97204.

Seed starting schedule

Radishes dates for Portland, OR

Step	Date	How to use it
Direct Sow	March 4, 2026	Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Portland?

Portland (ZIP 97204) has an average last spring frost around Apr 1.

First frost

When is the first frost in Portland?

The average first fall frost is around Nov 10, giving about 223 frost-free days.

Season map

Radishes windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Direct sow

Mar 4

Harvest

Apr 1

Frost watch

Oct 13

Reminder workflow

Every date has a next action

Direct sow radishesMar 4

Last frost windowApr 1

First radishes harvest windowApr 1

Last radishes sowing targetOct 13

Signal	Value	Why it matters
Last frost estimate	April 1, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	November 10, 2026	Fall planting counts backward from this date.
Season length	223 days	Longer seasons can support succession crops.
Spacing	1-2 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

Portland frost history and USDA zone 9a shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

Oregon State University 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

Radishes timing notes

Fast crop; harvest promptly before roots get woody. Radishes prefers full sun, 1-2 in spacing, and soil near 40 F+.

For fall, count backward from Nov 10. A conservative last sowing target is around Oct 13.