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When to Plant Valerian in Columbia County, WA

Columbia County, Washington Zone 7a May

May to-do list for Columbia County, Washington

A quick May briefing for Columbia County, Washington gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 28
Avg. first frost October 11
Soil temp (4") 56°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
  1. Move valerian from tray to bed

    Frost risk is low now in Columbia County, Washington. If you've been covering beds overnight, you can stop.

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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.

Columbia County, Washington is in USDA Zone 7a. The average last spring frost is April 28 and the first fall frost is October 11, giving you a growing season of approximately 166 days.

At an elevation of 3,157 feet, Columbia County receives approximately 21.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Valerian during the growing season.

Columbia County, WA (Zone 7a) Moderate season
166 days
Last Spring Frost April 28
166 growing days
First Fall Frost October 11
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Columbia County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 25 🍅 Harvest: Aug 29 – Dec 5
Recommended (50%) ✗ May not fit
Transplant: May 5 🍅 Harvest: Sep 8 – Dec 15
Safe Start (90%) ✓ Fits season (296 days to spare)
Transplant: May 25 🍅 Harvest: Sep 28 – Jan 4

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 Columbia County

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

Soil pH

Your soil pH (5.5–6.5) is within Valerian's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Valerian will thrive.

How to Plant Valerian

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 677 gal / 100 sq ft

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 3" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.3" 4" 🚿 Regular watering
Sep 4.3" 0.9" 3.4" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 3" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Columbia 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 needs ~2,625 GDD — county provides 2,905 GDD Good fit

Valerian Planting Timeline — Columbia County, WA

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 – May 19
Harvest September 8 Sep 8 – Dec 15

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September Harvest
October Harvest
November Harvest
December Harvest
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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: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

166 days in Columbia County

Growing Tips for Valerian in Columbia County

Direct sow Valerian outdoors after April 28 in Columbia County when soil has warmed and frost danger has passed.

Your 166.0-day growing season in Columbia County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Columbia County receives only 21" 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 →

Frequently Asked Questions

When should I plant Valerian in Columbia County, WA?

Columbia County is in Zone 7a with an average last frost of April 28. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.

What planting zone is Columbia County, WA?

Columbia County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 28 and first fall frost is October 11.

🌱

Your Columbia County Garden Planner — Free

A 24-page printable planner built for Columbia County (Zone 7a). 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 Columbia 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.