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When to Plant Valerian in Carbon County, UT

Carbon County, Utah Zone 6a May

Your May game plan for Carbon County, Utah

We've pulled the most time-sensitive tasks for Carbon County, Utah this May and put them front and centre. Tackle them in order.

Avg. last frost May 17
Avg. first frost September 27
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant valerian

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Carbon County, Utah is in USDA Zone 6a. The average last spring frost is May 17 and the first fall frost is September 27, giving you a growing season of approximately 133 days.

At an elevation of 5,755 feet, Carbon County receives approximately 14.2 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. With low rainfall, drip irrigation is essential for growing Valerian successfully. Mulch heavily to conserve soil moisture.

Carbon County, UT (Zone 6a) Short season
133 days
Last Spring Frost May 17
133 growing days
First Fall Frost September 27

Carbon County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 14 🍅 Harvest: Sep 17 – Nov 26
Recommended (50%) ✗ May not fit
Transplant: May 24 🍅 Harvest: Sep 27 – Dec 6
Safe Start (90%) ✗ May not fit
Transplant: Jun 15 🍅 Harvest: Oct 19 – Dec 28

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 Carbon County

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

Soil pH

Your soil pH (6.4–8.3) is more alkaline than Valerian prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 783 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.3" 3" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Carbon 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 1,729 GDD May not mature

Valerian Planting Timeline — Carbon County, UT

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors May 24 May 24 – Jun 7
Harvest September 27 Sep 27 – Dec 6

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

133 days in Carbon County

Growing Tips for Valerian in Carbon County

Direct sow Valerian outdoors after May 17 in Carbon County when soil has warmed and frost danger has passed.

Your 133.0-day growing season in Carbon County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Carbon County receives only 14" 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 Carbon County, UT?

Carbon County is in Zone 6a with an average last frost of May 17. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carbon County, UT?

Carbon County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 17 and first fall frost is September 27.

🌱

Your Carbon County Garden Planner — Free

A 24-page printable planner built for Carbon County (Zone 6a). 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 Carbon County, UT. Local conditions may vary. Last updated: May 2026.

Sources & credits

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