When to Plant Valerian in Walla Walla County, WA
Valerian is a tall perennial herb with fragrant white or pink flower clusters, valued for its root which is used as a natural sleep aid. It attracts pollinators and earthworms.
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 Valerian 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 Valerian's growing requirements.
Soil pH
Your soil pH (5.2–6.4) overlaps with Valerian's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Walla Walla County is excellent for Valerian — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Valerian will thrive.
How to Plant Valerian
Plant Water Budget
Monthly Watering Guide for Valerian
Valerian needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Valerian 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.
Valerian 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.
Valerian Planting Timeline — Walla Walla County, WA
Valerian Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
| Harvest | August 31 | Aug 31 – Nov 9 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
120–180 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
178 days in Walla Walla County
Growing Tips for Valerian in Walla Walla County
Direct sow Valerian outdoors after April 20 in Walla Walla County when soil has warmed and frost danger has passed.
Your 178.0-day growing season in Walla Walla County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.
Walla Walla County receives only 24" of rain annually. Valerian needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors and transplant after last frost. Harvest roots in fall of the second year. Deadhead flowers unless you want self-seeding. Cats are attracted to valerian root.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Valerian in Other Locations
Frequently Asked Questions
When should I plant Valerian in Walla Walla County, WA?
Walla Walla County is in Zone 6b with an average last frost of April 20. Plan your Valerian 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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