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When to Plant Crosne in Multnomah 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.

Multnomah County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Crosne to ensure they mature before fall.

Multnomah County, OR (Zone 8b) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Multnomah County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

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 14 🍅 Harvest: Sep 15 – Nov 17
Safe Start (90%) ✗ May not fit
Transplant: May 9 🍅 Harvest: Oct 10 – Dec 12

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
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 926 gal / 100 sq ft
Crosne needs ~2,275 GDD — county provides 2,548 GDD Good fit

Crosne Planting Timeline โ€” Multnomah County, OR

Crosne Planting Calendar

Activity When Date Range
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 18 Aug 18 โ€“ Sep 1
Harvest September 1 Sep 1 โ€“ Nov 3

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Direct Sow
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

196 days

Growing Tips for Multnomah 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 Multnomah County, OR?

Multnomah County is in Zone 8b with an average last frost of April 14. Plan your Crosne planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Multnomah County, OR?

Multnomah County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Multnomah County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

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