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When to Plant Crosne in Washington County, OR

Crosne (Chinese artichoke) produces small, segmented white tubers with a crunchy texture and mild artichoke-nutty flavor. They are a rare delicacy in French cuisine.

Washington County, Oregon is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 27, giving you a growing season of approximately 195 days.

At an elevation of 352 feet, Washington County receives approximately 47.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Crosne during the growing season.

Washington County, OR (Zone 8b) Moderate season
195 days
Last Spring Frost April 15
195 growing days
First Fall Frost October 27

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 8 🍅 Harvest: Sep 9 – Nov 11
Recommended (50%) ✗ May not fit
Transplant: Apr 15 🍅 Harvest: Sep 16 – Nov 18
Safe Start (90%) ✗ May not fit
Transplant: May 8 🍅 Harvest: Oct 9 – Dec 11

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Crosne needs ~2,406 GDD — county provides 2,681 GDD Good fit

Crosne Planting Timeline โ€” Washington County, OR

Crosne Planting Calendar

Activity When Date Range
Direct Sow April 1 Apr 1 โ€“ Apr 22
Fall Sowing August 18 Aug 18 โ€“ Sep 1
Harvest September 2 Sep 2 โ€“ Nov 4

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May โ€”
June โ€”
July โ€”
August Fall Sowing
September Fall Sowing Harvest
October Harvest
November Harvest
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

150โ€“200 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8b

Growing Season

195 days

Growing Tips for Washington County

Plant tubers 3 inches deep in spring. Mark the location well as plants die back. Harvest in late fall after frost. Leave some tubers in ground for next year. Very labor-intensive to harvest.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Crosne in Washington County, OR?

Washington County is in Zone 8b with an average last frost of April 15. Plan your Crosne planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Washington County, OR?

Washington County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 15 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Washington County gardeners in Zone 8b 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 Washington County, OR. Local conditions may vary. Last updated: April 2026.