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When to Plant Lemongrass in Clark County, WA

Clark County, Washington Zone 8b May

Your May game plan for Clark County, Washington

Your Clark County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 14
Avg. first frost October 27
Soil temp (4") 72°F
Watering High
Pest pressure High
Daylight 14.7 hrs
June will be here before you know it — start on
  • Starting indoors: lemongrass

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Lemongrass is a tropical grass with a strong citrus aroma used extensively in Southeast Asian cuisine. The swollen stem bases are the most flavorful part.

Clark County, Washington is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 482 feet, Clark County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lemongrass during the growing season.

Clark County, WA (Zone 8b) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jul 8 – Oct 7
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jul 14 – Oct 13
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Aug 8 – Nov 7

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 Clark County

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

Soil pH

Your soil pH (5.4–6.3) overlaps with Lemongrass's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Lemongrass is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (4.8%) — Lemongrass will thrive.

How to Plant Lemongrass

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

Succession Planting Lemongrass

3
successive plantings in your 196-day season

Sow every 8.6 weeks. Last sowing by Jun 29 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,910 gal / 100 sq ft

Monthly Watering Guide for Lemongrass

Lemongrass needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Lemongrass Needs Rainfall You Supplement Action
Jan 5.4" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 6.5" 2.6" 3.9" 🚿 Regular watering
May 6.5" 2.5" 4" 🚿 Regular watering
Jun 6.5" 1.7" 4.8" 🚿 Regular watering
Jul 6.5" 0.6" 5.9" 🚿 Regular watering
Aug 6.5" 0.8" 5.7" 🚿 Regular watering
Sep 6.5" 1.5" 5" 🚿 Regular watering
Oct 6.5" 3.1" 3.4" 🚿 Regular watering
Nov 5.9" 0" ❄️ Dormant
Dec 7.2" 0" ❄️ Dormant

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

Lemongrass 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.

Lemongrass needs ~1,341 GDD — county provides 2,695 GDD Excellent fit

Lemongrass Planting Timeline — Clark County, WA

Lemongrass Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest July 14 Jul 14 – Oct 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

75–120 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

196 days in Clark County

Growing Tips for Lemongrass in Clark County

Direct sow Lemongrass outdoors after April 14 in Clark County when soil has warmed and frost danger has passed.

Common pests for Lemongrass in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

General growing tips

Start from divisions or store-bought stalks rooted in water. Grow in rich, moist soil with full sun. In cold climates, grow in containers and overwinter indoors.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemongrass in Clark County, WA?

Clark County is in Zone 8b with an average last frost of April 14. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, WA?

Clark County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 27.

🌱

Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 8b). 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 Clark 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.