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When to Plant Mache in Clark County, WA

Clark County, Washington Zone 8b May

Top priorities for Clark County, Washington gardeners in May

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
  1. Sow mache in trays indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Pick mache

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to June
  • First harvests: mache

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Mache (corn salad) is a cold-hardy salad green with small, rounded, tender leaves and a mild, nutty flavor. It thrives in cool weather and even overwinters in many climates.

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 Mache 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 (116 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 20 – Jun 24
Recommended (50%) ✓ Fits season (119 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 26 – Jun 30
Safe Start (90%) ✓ Fits season (117 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 20 – Jul 25

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 Mache's growing requirements.

Soil pH

Your soil pH (5.4–6.3) is more acidic than Mache prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Mache.

Organic Matter

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

How to Plant Mache

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Mache

5
successive plantings in your 196-day season

Sow every 4.6 weeks. Last sowing by Aug 28 to harvest before frost.

For a dedicated fall crop, sow by Aug 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 776 gal / 100 sq ft

Monthly Watering Guide for Mache

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

Month Mache Needs Rainfall You Supplement Action
Jan 5.4" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 4.3" 3.1" 1.2" 💧 Light 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.

Mache 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.

Mache needs ~688 GDD — county provides 2,695 GDD Excellent fit

Mache Planting Timeline — Clark County, WA

Mache Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest May 26 May 26 – Jun 30
Fall Sowing August 18 Aug 18 – Sep 1

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

196 days in Clark County

Growing Tips for Mache in Clark County

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

Your generous 196.0-day season in Clark County allows multiple plantings of Mache. Sow every 20.0 days for continuous harvest.

General growing tips

Direct sow in early spring or late summer for fall and winter harvest. Seeds need light to germinate so press gently into soil surface. Harvest whole rosettes.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mache in Clark County, WA?

Clark County is in Zone 8b with an average last frost of April 14. Plan your Mache 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.