When to plant basil in Oregon
Oregon’s average last spring frost is April 20, and the first fall frost typically arrives around October 18 — about 181 frost-free days (USDA zones 4b, 5b, 6b, 7b, 8b, 9a, 9b). Basil needs 30–60 days to mature, which fits comfortably within Oregon's growing season.
Oregon covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant basil in Oregon: the short answer
For a spring planting, plant out Apr 27 – May 14, with seeds started indoors Mar 9 – Mar 23. Wait until the soil is at least 65°F and frost is over.
Succession sow again in Oregon: May 25 · Jun 15 · Jul 6 · Jul 27 · Aug 17
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow basil in Oregon, step by step
- Start seeds indoors (Mar 9 – Mar 23). Sow seeds ⅛ inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 80°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 10 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Plant out (Apr 27 – May 14). Space plants about 10 inches apart in rows 12 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, Japanese beetle, slugs. Diseases and disorders: basil downy mildew, fusarium wilt, damping off.
- Harvest (from about Jun 3 – Jul 3). Basil takes 30-60 days to reach harvest. Cold soil stalls it - wait for warm nights. Pinch above a leaf pair every couple of weeks and remove flower buds to keep leaves coming. Downy mildew-resistant varieties are worth seeking out.
Figures come from our crop data; dates use Oregon’s average frost dates. More in the full basil growing guide.
Basil planting dates by USDA zone in Oregon
Oregon spans USDA zones 4b, 5b, 6b, 7b, 8b, 9a, 9b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the basil dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant basil |
|---|---|---|---|---|---|
| Zone 4 | May 10 | Sep 25 | 135 days | Mar 29 – Apr 12 | May 17 – Jun 3 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | Mar 19 – Apr 2 | May 7 – May 24 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Mar 4 – Mar 18 | Apr 22 – May 9 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Feb 22 – Mar 8 | Apr 12 – Apr 29 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | Feb 6 – Feb 20 | Mar 27 – Apr 13 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | Jan 9 – Jan 23 | Feb 27 – Mar 16 |
When to plant basil in nearby states
| State | Last frost | Plant out |
|---|---|---|
| Oregon (this page) | April 20 | Apr 27 – May 14 |
| Washington | April 20 | Apr 27 – May 14 |
Questions gardeners in Oregon ask
When is the best time to plant basil in Oregon?
Plant basil transplants outdoors in Oregon between April 27 and May 14. That timing is set by Oregon's average last spring frost of April 20; Oregon spans several climates, so cooler and higher parts of the state run later.
When should I start basil seeds indoors in Oregon?
Start seeds indoors between March 9 and March 23, about 5 weeks before the last frost, so the seedlings are ready to plant out from April 27.
What is the latest I can plant basil in Oregon?
About September 18. Basil needs at least 30 days to mature, and frost around October 18 ends the season, so later plantings risk being cut short.
When will basil planted in Oregon be ready to harvest?
Planted on time, basil is usually ready from about June 3 to July 3, 30-60 days after planting.
When is the last frost in Oregon?
On average around April 20, with the first fall frost around October 18 - about 181 frost-free days. Your town may differ by two weeks or more.