When to Plant Basil in Oregon
The king of herbs. Basil and tomatoes are best friends in the garden and in the kitchen.
The Short Answer
Oregon Frost Dates
Your planting dates depend on which part of Oregon you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Willamette Valley | 8a, 8b | Mar 25 - Apr 15 | Oct 15 - Nov 10 |
| Portland Metro | 8b, 9a | Mar 15 - Apr 5 | Oct 25 - Nov 15 |
| Central/Eastern Oregon | 5a, 5b, 6a, 6b | May 10 - Jun 1 | Sep 10 - Oct 1 |
| Southern Oregon Coast | 8b, 9a, 9b | Mar 5 - Mar 25 | Nov 5 - Nov 25 |
Basil Planting Schedule for Oregon
Willamette Valley (Zones 8a, 8b)
Average last frost: Mar 25 - Apr 15 · Average first frost: Oct 15 - Nov 10
Portland Metro (Zones 8b, 9a)
Average last frost: Mar 15 - Apr 5 · Average first frost: Oct 25 - Nov 15
Central/Eastern Oregon (Zones 5a, 5b, 6a, 6b)
Average last frost: May 10 - Jun 1 · Average first frost: Sep 10 - Oct 1
Southern Oregon Coast (Zones 8b, 9a, 9b)
Average last frost: Mar 5 - Mar 25 · Average first frost: Nov 5 - Nov 25
Growing Basil in Oregon
Basil in Oregon's Climate
Basil thrives in your warm climate and can produce for 5-6 months or more. In the deep South, basil may survive mild winters in sheltered locations. African Blue basil and Thai basil handle heat better than sweet Genovese. Watch for downy mildew in humid conditions — it's become a significant basil disease in warm, humid climates over the past decade.
Soil Considerations for Oregon
Rich volcanic soils in Willamette Valley. Dry, alkaline soils east of Cascades. Acidic forest soils on coast. Generally excellent for gardening in valleys. Make sure soil has warmed to at least 60°F before planting basil outside.
Oregon Climate & Growing Season
Dramatic east-west climate divide. Wet, mild winters west of Cascades. Dry, cold winters east. Year-round gardening possible in mild western valleys. Basil cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Oregon: Willamette Valley (8a, 8b) has a last frost around Mar 25 - Apr 15, while Southern Oregon Coast (8b, 9a, 9b) sees frost end around Mar 5 - Mar 25. This difference matters for basil — transplant timing shifts by several weeks across the state.
Growing Tips
Pinch off flower buds to keep leaves producing. Harvest from the top down, cutting just above a leaf pair. Succession plant for season-long supply.
Companion Planting
Plant basil alongside these companions for better growth:
Keep basil away from:
The Bottom Line
Last reviewed: March 29, 2026