When to Plant Asparagus in Umatilla County, OR
Asparagus is a long-lived perennial vegetable that produces tender spears each spring for 15-20 years once established. It requires patience but rewards with reliable harvests.
Umatilla County, Oregon is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.
At an elevation of 2,195 feet, Umatilla County receives approximately 14.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Asparagus during the growing season. With low rainfall, drip irrigation is essential for growing Asparagus successfully. Mulch heavily to conserve soil moisture.
Umatilla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.8
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 Umatilla County
How your county's soil matches Asparagus's growing requirements.
Soil pH
Your soil pH (5.2–6.8) is more acidic than Asparagus prefers (6.5–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Umatilla County is excellent for Asparagus — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Asparagus will thrive.
How to Plant Asparagus
Plant Water Budget
Asparagus Planting Timeline — Umatilla County, OR
Asparagus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 7 | May 7 – May 21 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · 1-2 times/week
📅 Days to Maturity
730–1095 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6a
📆 Growing Season
180 days in Umatilla County
Growing Tips for Asparagus in Umatilla County
Direct sow Asparagus outdoors after April 23 in Umatilla County when soil has warmed and frost danger has passed.
Your 180.0-day growing season in Umatilla County is tight for Asparagus (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant crowns in deep trenches with compost. Do not harvest spears for the first two years to allow root establishment. Mulch heavily to suppress weeds and retain moisture.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Asparagus in Other Locations
Frequently Asked Questions
When should I plant Asparagus in Umatilla County, OR?
Umatilla County is in Zone 6a with an average last frost of April 23. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.
What planting zone is Umatilla County, OR?
Umatilla County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 20.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Umatilla County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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