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When to Plant Cilantro in Spokane County, WA

Spokane County, Washington Zone 6b May

Your May game plan for Spokane County, Washington

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 11
Avg. first frost September 27
Soil temp (4") 61°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Move cilantro from tray to bed

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

Get ahead of June
  • Starting indoors: cilantro
  • First harvests: cilantro

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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.

Spokane County, Washington is in USDA Zone 6b. The average last spring frost is May 11 and the first fall frost is September 27, giving you a growing season of approximately 139 days.

At an elevation of 1,645 feet, Spokane County receives approximately 20.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Cilantro during the growing season.

Spokane County, WA (Zone 6b) Short season
139 days
Last Spring Frost May 11
139 growing days
First Fall Frost September 27

Spokane County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Mar 26 Transplant: Apr 23 🍅 Harvest: Jun 4 – Aug 6
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 15 – Aug 17
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: May 8 Transplant: Jun 5 🍅 Harvest: Jul 17 – Sep 18

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 Spokane County

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

Soil pH

Your soil pH (5.5–6.2) is more acidic than Cilantro prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Spokane County is excellent for Cilantro — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.4%) — Cilantro will thrive.

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Cilantro

4
successive plantings in your 139-day season

Sow every 4.6 weeks. Last sowing by Jul 29 to harvest before frost.

For a dedicated fall crop, sow by Jul 19.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 3.1" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.7" 1.5" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 3.3" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Spokane County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cilantro 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" — every day above 50°F 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.

Cilantro needs ~912 GDD — county provides 2,536 GDD Excellent fit

Cilantro Planting Timeline — Spokane County, WA

Cilantro Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest June 15 Jun 15 – Aug 17
Fall Sowing July 19 Jul 19 – Aug 2

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

139 days in Spokane County

Growing Tips for Cilantro in Spokane County

Direct sow Cilantro outdoors after May 11 in Spokane County when soil has warmed and frost danger has passed.

Summer highs in Spokane County reach 91°F — grow Cilantro as a spring or fall crop. Use shade cloth if planting in summer.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Spokane County, WA?

Spokane County is in Zone 6b with an average last frost of May 11. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Spokane County, WA?

Spokane County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 11 and first fall frost is September 27.

🌱

Your Spokane County Garden Planner — Free

A 24-page printable planner built for Spokane County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Spokane County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.