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When to Plant Cilantro in Island County, WA

Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Island County, Washington is in USDA Zone 8a. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.

At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Cilantro during the growing season.

Island County, WA (Zone 8a) Long season
218 days
Last Spring Frost March 30
218 growing days
First Fall Frost November 3

Island County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Feb 15 Transplant: Mar 15 🍅 Harvest: Apr 26 – Jun 28
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Feb 23 Transplant: Mar 23 🍅 Harvest: May 4 – Jul 6
Safe Start (90%) ✓ Fits season (110 days to spare)
Start indoors: Mar 26 Transplant: Apr 23 🍅 Harvest: Jun 4 – Aug 6

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 239 gal / 100 sq ft
Cilantro needs ~688 GDD — county provides 2,997 GDD Excellent fit

Cilantro Planting Timeline โ€” Island County, WA

Cilantro Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 โ€“ Mar 9
Transplant Outdoors March 23 Mar 23 โ€“ Apr 6
Direct Sow March 16 Mar 16 โ€“ Apr 6
Fall Sowing August 25 Aug 25 โ€“ Sep 8
Harvest May 4 May 4 โ€“ Jul 6

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

40โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

218 days

Growing Tips for Island County

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Level Up Your Garden

Frequently Asked Questions

When should I plant Cilantro in Island County, WA?

Island County is in Zone 8a with an average last frost of March 30. Plan your Cilantro planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Island County, WA?

Island County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is March 30 and first fall frost is November 3.

๐ŸŒฑ

Plan Your Garden with Confidence

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