When to Plant Corn (Sweet) in Oregon
Nothing says summer like fresh sweet corn. Plant in blocks (not rows) for proper pollination.
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 |
Corn (Sweet) 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 Corn (Sweet) in Oregon
Corn (Sweet) in Oregon's Climate
Sweet corn hits the table earlier in warm climates — plant in March-April and harvest before northern states even think about planting. The goal is tasseling before consistent 95°F+ days, which can impair pollination. A second short-season crop in late July for fall harvest is possible in many warm zones.
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 corn (sweet) 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. Corn (Sweet) 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 corn (sweet) — transplant timing shifts by several weeks across the state.
Growing Tips
Plant in blocks of at least 4x4 for wind pollination. Corn is a heavy feeder — amend soil with compost before planting.
Companion Planting
Plant corn (sweet) alongside these companions for better growth:
Keep corn (sweet) away from:
The Bottom Line
Last reviewed: March 29, 2026