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When to Plant Asparagus in Harney 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.

Harney County, Oregon is in USDA Zone 5b. The average last spring frost is June 17 and the first fall frost is September 6, giving you a growing season of approximately 81 days.

At an elevation of 679 feet, Harney County receives approximately 22.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Asparagus during the growing season.

Harney County, OR (Zone 5b) Very short season
81 days
Last Spring Frost June 17
81 growing days
First Fall Frost September 6

Harney County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jun 26
Recommended (50%) ✓ Fits season
Transplant: Jul 1
Safe Start (90%) ✓ Fits season
Transplant: Jul 8

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

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Asparagus needs ~13,916 GDD — county provides 1,235 GDD May not mature

Asparagus Planting Timeline โ€” Harney County, OR

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors July 1 Jul 1 โ€“ Jul 15

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June โ€”
July Transplant Outdoors
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

730โ€“1095 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

81 days

Growing Tips for Harney County

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

  • Garlic
  • Onion

Level Up Your Garden

Frequently Asked Questions

When should I plant Asparagus in Harney County, OR?

Harney County is in Zone 5b with an average last frost of June 17. Plan your Asparagus planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harney County, OR?

Harney County, Oregon is in USDA Hardiness Zone 5b. The average last spring frost is June 17 and first fall frost is September 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Harney County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Harney County, OR. Local conditions may vary. Last updated: April 2026.