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When to Plant Celery in Lewis County, WA

Lewis County, Washington Zone 8a May

This month in Lewis County, Washington

We've pulled the most time-sensitive tasks for Lewis County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost April 25
Avg. first frost October 24
Soil temp (4") 66°F
Watering High
Pest pressure Moderate
Daylight 14.8 hrs
  1. Get celery seeds going inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Lewis County, Washington is in USDA Zone 8a. The average last spring frost is April 25 and the first fall frost is October 24, giving you a growing season of approximately 182 days.

At an elevation of 327 feet, Lewis County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Celery during the growing season.

Lewis County, WA (Zone 8a) Moderate season
182 days
Last Spring Frost April 25
182 growing days
First Fall Frost October 24
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Lewis County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 6 – Aug 31
Recommended (50%) ✓ Fits season (42 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jul 18 – Sep 12
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: May 20 Transplant: Jun 24 🍅 Harvest: Sep 16 – Nov 11

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 Lewis County

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Celery prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.3%) — Celery will thrive.

How to Plant Celery

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Celery

2
successive plantings in your 182-day season

Sow every 9.1 weeks. Last sowing by Jun 26 to harvest before frost.

For a dedicated fall crop, sow by Aug 15.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 711 gal / 100 sq ft

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Celery Needs Rainfall You Supplement Action
Jan 5.6" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 5.6" 2.8" 2.8" 🚿 Regular watering
May 5.6" 2" 3.6" 🚿 Regular watering
Jun 5.6" 1.3" 4.3" 🚿 Regular watering
Jul 5.6" 0.6" 5" 🚿 Regular watering
Aug 5.6" 0.6" 5" 🚿 Regular watering
Sep 5.6" 1.4" 4.2" 🚿 Regular watering
Oct 5.6" 3.4" 2.2" 💧 Light watering
Nov 6.3" 0" ❄️ Dormant
Dec 5.7" 0" ❄️ Dormant

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

Celery 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.

Celery needs ~1,450 GDD — county provides 2,639 GDD Excellent fit

Celery Planting Timeline — Lewis County, WA

Celery Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 11 Apr 11 – May 2
Harvest July 18 Jul 18 – Sep 12
Fall Sowing August 15 Aug 15 – Aug 29

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 1-2 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

182 days in Lewis County

Growing Tips for Celery in Lewis County

Direct sow Celery outdoors after April 25 in Lewis County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celery in Lewis County, WA?

Lewis County is in Zone 8a with an average last frost of April 25. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis County, WA?

Lewis County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 25 and first fall frost is October 24.

🌱

Your Lewis County Garden Planner — Free

A 24-page printable planner built for Lewis County (Zone 8a). 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 Lewis 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.