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When to Plant Cardoon in Grays Harbor County, WA

Cardoon is a large thistle relative of the artichoke, grown for its edible leaf stalks. It has dramatic silvery foliage and makes a striking ornamental as well.

Grays Harbor County, Washington is in USDA Zone 8a. The average last spring frost is April 27 and the first fall frost is October 23, giving you a growing season of approximately 179 days.

At an elevation of 65 feet, Grays Harbor County receives approximately 39.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Cardoon during the growing season.

Grays Harbor County, WA (Zone 8a) Moderate season
179 days
Last Spring Frost April 27
179 growing days
First Fall Frost October 23

Grays Harbor County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 28 🍅 Harvest: Sep 1 – Oct 13
Recommended (50%) ✗ May not fit
Transplant: May 11 🍅 Harvest: Sep 14 – Oct 26
Safe Start (90%) ✓ Fits season (11 days to spare)
Transplant: May 26 🍅 Harvest: Sep 29 – Nov 10

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 Grays Harbor County

How your county's soil matches Cardoon's growing requirements.

Soil pH

Your soil pH (5.5โ€“6.7) overlaps with Cardoon's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Grays Harbor County is excellent for Cardoon โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.5%) โ€” Cardoon will thrive.

How to Plant Cardoon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 120 gal / 100 sq ft

Monthly Watering Guide for Cardoon

Cardoon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Cardoon Needs Rainfall You Supplement Action
Jan โ€” 5.9" 0" โ„๏ธ Dormant
Feb โ€” 4.3" 0" โ„๏ธ Dormant
Mar โ€” 4.1" 0" โ„๏ธ Dormant
Apr 4.3" 3.3" 1" ๐Ÿ’ง Light watering
May 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Jun 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Jul 4.3" 0.6" 3.7" ๐Ÿšฟ Regular watering
Aug 4.3" 0.8" 3.5" ๐Ÿšฟ Regular watering
Sep 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Oct 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Nov โ€” 5.9" 0" โ„๏ธ Dormant
Dec โ€” 5.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Grays Harbor County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Cardoon Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Cardoon needs ~2,160 GDD — county provides 2,864 GDD Excellent fit

Cardoon Planting Timeline โ€” Grays Harbor County, WA

Cardoon Planting Calendar

Activity When Date Range
Transplant Outdoors May 11 May 11 โ€“ May 25
Harvest September 14 Sep 14 โ€“ Oct 26

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

120โ€“150 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

179 days in Grays Harbor County

Growing Tips for Cardoon in Grays Harbor County

Direct sow Cardoon outdoors after April 27 in Grays Harbor County when soil has warmed and frost danger has passed.

Common pests for Cardoon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Blanch stalks by wrapping with cardboard or tying leaves together 3-4 weeks before harvest. Provide deep, rich soil and consistent moisture. Protect from hard frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cardoon in Grays Harbor County, WA?

Grays Harbor County is in Zone 8a with an average last frost of April 27. Plan your Cardoon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grays Harbor County, WA?

Grays Harbor County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 27 and first fall frost is October 23.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

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 Grays Harbor County, WA. Local conditions may vary. Last updated: April 2026.