When to Plant Mache in Walla Walla County, WA
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.
Walla Walla County, Washington is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.
At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mache during the growing season.
Walla Walla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
Drainage
Well Drained
Plant Planting Risk Windows
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 Walla Walla County
How your county's soil matches Mache's growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Mache prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Walla Walla County is excellent for Mache — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Mache will thrive.
How to Plant Mache
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Mache
Sow every 4.6 weeks. Last sowing by Aug 16 to harvest before frost.
For a dedicated fall crop, sow by Aug 06.
Plant Water Budget
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 | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| May | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jun | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jul | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Aug | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Sep | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Oct | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Walla Walla 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 Planting Timeline — Walla Walla County, WA
Mache Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 1 | Jun 1 – Jul 6 |
| Fall Sowing | August 6 | Aug 6 – Aug 20 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| 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 6b
📆 Growing Season
178 days in Walla Walla County
Growing Tips for Mache in Walla Walla County
Direct sow Mache outdoors after April 20 in Walla Walla County when soil has warmed and frost danger has passed.
Your generous 178.0-day season in Walla Walla County allows multiple plantings of Mache. Sow every 20.0 days for continuous harvest.
Walla Walla County receives only 24" of rain annually. Mache needs consistent moisture — 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 →
Mache in Other Locations
Frequently Asked Questions
When should I plant Mache in Walla Walla County, WA?
Walla Walla County is in Zone 6b with an average last frost of April 20. Plan your Mache planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walla Walla County, WA?
Walla Walla County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 15.
Plan Your Garden with Confidence
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