When to Plant Sweet Corn in Wasco County, OR
Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.
Wasco County, Oregon is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.
At an elevation of 432 feet, Wasco County receives approximately 35.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.
Wasco County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.3
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Plant Water Budget
Sweet Corn Planting Timeline — Wasco County, OR
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 2 | Jul 2 – Aug 13 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
USDA Zone
Zone 6b
Growing Season
172 days
Growing Tips for Wasco County
Plant in blocks of at least 4 rows for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Sweet Corn in Other Locations
Frequently Asked Questions
When should I plant Sweet Corn in Wasco County, OR?
Wasco County is in Zone 6b with an average last frost of April 23. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Wasco County, OR?
Wasco County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 12.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Wasco County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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