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When to Plant Mache in Clark County, ID

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, Idaho is in USDA Zone 4a. The average last spring frost is June 7 and the first fall frost is September 10, giving you a growing season of approximately 95 days.

At an elevation of 7,493 feet, Clark County receives approximately 21.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Mache to ensure they mature before fall.

Clark County, ID (Zone 4a) Very short season
95 days
Last Spring Frost June 7
95 growing days
First Fall Frost September 10

Clark County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Apr 11 Transplant: May 23 🍅 Harvest: Jul 4 – Aug 8
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Apr 26 Transplant: Jun 7 🍅 Harvest: Jul 19 – Aug 23
Safe Start (90%) ✓ Fits season (28 days to spare)
Start indoors: May 10 Transplant: Jun 21 🍅 Harvest: Aug 2 – Sep 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.

Soil Compatibility in Clark County

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

Soil pH

Your soil pH (6.8โ€“7.8) overlaps with Mache's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Mache.

How to Plant Mache

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Mache

2
successive plantings in your 95-day season

Sow every 4.6 weeks. Last sowing by Jul 12 to harvest before frost.

For a dedicated fall crop, sow by Jun 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 32 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr โ€” 2.5" 0" โ„๏ธ Dormant
May โ€” 2.5" 0" โ„๏ธ Dormant
Jun 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Jul 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Aug 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Sep 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Oct โ€” 1.8" 0" โ„๏ธ Dormant
Nov โ€” 1.6" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in Clark County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~575 GDD — county provides 1,092 GDD Excellent fit

Mache Planting Timeline โ€” Clark County, ID

Mache Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 โ€“ May 10
Transplant Outdoors June 7 Jun 7 โ€“ Jun 21
Direct Sow May 31 May 31 โ€“ Jun 21
Harvest July 19 Jul 19 โ€“ Aug 23
Fall Sowing June 18 Jun 18 โ€“ Jul 2

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

95 days in Clark County

Growing Tips for Mache in Clark County

Direct sow Mache outdoors after June 07 in Clark County when soil has warmed and frost danger has passed.

Clark County receives only 22" of rain annually. Mache needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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, ID?

Clark County is in Zone 4a with an average last frost of June 7. Plan your Mache planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clark County, ID?

Clark County, Idaho is in USDA Hardiness Zone 4a. The average last spring frost is June 7 and first fall frost is September 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clark County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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, ID. Local conditions may vary. Last updated: April 2026.