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When to Plant Crosne in Whatcom County, WA

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.

Whatcom County, Washington is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Crosne during the growing season.

Whatcom County, WA (Zone 7b) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Whatcom County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Mar 25 🍅 Harvest: Aug 26 – Oct 28
Recommended (50%) ✗ May not fit
Transplant: Apr 6 🍅 Harvest: Sep 7 – Nov 9
Safe Start (90%) ✗ May not fit
Transplant: May 6 🍅 Harvest: Oct 7 – Dec 9

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 Only during dry spells
Season total 2 gal / 100 sq ft
Crosne needs ~2,406 GDD — county provides 2,832 GDD Good fit

Crosne Planting Timeline โ€” Whatcom County, WA

Crosne Planting Calendar

Activity When Date Range
Direct Sow March 23 Mar 23 โ€“ Apr 13
Fall Sowing August 20 Aug 20 โ€“ Sep 3
Harvest August 24 Aug 24 โ€“ Oct 26

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 Harvest
September Fall Sowing Harvest
October Harvest
November โ€”
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 7b

Growing Season

206 days

Growing Tips for Whatcom 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 Whatcom County, WA?

Whatcom County is in Zone 7b with an average last frost of April 6. Plan your Crosne planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Whatcom County, WA?

Whatcom County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Whatcom County gardeners in Zone 7b 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 Whatcom County, WA. Local conditions may vary. Last updated: April 2026.