When to Plant Onion in Wasco County, OR
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
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 Onion 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.
Soil Compatibility in Wasco County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.2–6.3) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Wasco County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.2%) — Onion will thrive.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Onion Planting Timeline — Wasco County, OR
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Fall Sowing | August 3 | Aug 3 – Aug 17 |
| Harvest | July 23 | Jul 23 – Sep 10 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
172 days in Wasco County
Growing Tips for Onion in Wasco County
Direct sow Onion outdoors after April 23 in Wasco County when soil has warmed and frost danger has passed.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Wasco County, OR?
Wasco County is in Zone 6b with an average last frost of April 23. Plan your Onion 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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