When to plant basil in Portland, OR

Start basil from seed indoors Mar 29 – Apr 12, then plant the young plants in the garden in Portland May 10 – Jun 7.

Moderate Plant young plants (starts)

Why these dates

Portland's typical last spring frost is March 13. Frost kills basil, and warm-season crops also need warm soil. Soil here stays cold for weeks after the last frost, so planting waits until about May 10.

West-side valleys. The Willamette Valley, Puget Sound and southern Oregon valleys. Long frost-free seasons, but soil stays cold and wet into May, so warm crops wait for warm soil, not just the last frost.

Difficulty: Moderate
Sun: Full sun
Spacing: 12 inches apart
Planting depth: Plant starts at the depth they grew in the pot
Frost: Killed by frost
First harvest: About 60 days after planting

Step by step

Start seeds indoors Mar 29 – Apr 12 in trays or small pots under a grow light or in your sunniest window. Or skip this step and buy young plants (starts) at a garden center.
Harden off the young plants: about a week before planting, set them outside for a few hours a day, a little longer each day.
Plant them in the garden May 10 – Jun 7, 12 inches apart. Plant starts at the depth they grew in the pot.
Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
Harvest: Pinch off the top pair of leaves often so plants bush out, and remove flower buds.

Varieties that do well here

Genovese
Thai
Spicy Globe

Watch out for

Cold. Basil blackens below about 40°F, so it goes out last and comes in at the first chilly night.

Blackens below about 40°F, so it's the last thing to go out.

Common questions

When is the last frost in Portland, OR?

Typically March 13. In 9 years out of 10, frost is over by April 1. These are 1991–2020 NOAA climate normals for Portland International Airport.

Is it too late to plant basil in Portland?

The spring planting window runs through June 7. Later plantings may not have time to produce before the first fall frost, which usually arrives around November 19.

When should I start basil from seed indoors in Portland?

March 29 to April 12, which is 6 to 4 weeks before the May 10 planting date. Or buy young plants at a garden center instead.