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When to Plant Valerian in Idaho County, ID

Idaho County, Idaho Zone 6b May

Your May planting checklist for Idaho County, Idaho

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 39°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: valerian

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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.

Idaho County, Idaho is in USDA Zone 6b. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 6,736 feet, Idaho County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Valerian to ensure they mature before fall.

Idaho County, ID (Zone 6b) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20
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Idaho County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Sep 28 – Dec 7
Recommended (50%) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Oct 9 – Dec 18
Safe Start (90%) ✓ Fits season (269 days to spare)
Transplant: Jul 1 🍅 Harvest: Nov 4 – Jan 13

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 Idaho County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Valerian prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Valerian.

How to Plant Valerian

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 119 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Idaho 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 ~1,950 GDD — county provides 1,482 GDD May not mature

Valerian Planting Timeline — Idaho County, ID

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors June 5 Jun 5 – Jun 19
Harvest October 9 Oct 9 – Dec 18

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

114 days in Idaho County

Growing Tips for Valerian in Idaho County

Direct sow Valerian outdoors after May 29 in Idaho County when soil has warmed and frost danger has passed.

Your 114.0-day growing season in Idaho County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Idaho 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 →

Frequently Asked Questions

When should I plant Valerian in Idaho County, ID?

Idaho County is in Zone 6b with an average last frost of May 29. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.

What planting zone is Idaho County, ID?

Idaho County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 29 and first fall frost is September 20.

🌱

Your Idaho County Garden Planner — Free

A 24-page printable planner built for Idaho County (Zone 6b). 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 Idaho County, ID. 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.