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When to plant Thyme in Clark County, ID

In Clark County, Thyme is a single-season spring crop — there's no second fall window. Plant June 14–June 28 for an 70–90-day harvest, finishing well before the September 10 first frost.

When to Plant Thyme in Clark County, ID

Thyme
Clark County, Idaho Zone 5b June

June in the garden — Clark County, Idaho

Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost June 7
Avg. first frost September 10
Soil temp (4") 42°F
Watering High
Pest pressure High
Daylight 15.3 hrs
  1. Move thyme into the garden

    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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Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.

Clark County, Idaho is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 10, giving you a growing season of approximately 95 days.

At an elevation of 7,493 feet, Clark County receives approximately 21.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Thyme to ensure they mature before fall.

Clark County, ID (Zone 5b) Very short season
95 days
Last Spring Frost June 7
95 growing days
First Fall Frost September 10

Clark County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Thyme Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 30 🍅 Harvest: Aug 8 – Oct 10
Recommended (50%) ✗ May not fit
Transplant: Jun 14 🍅 Harvest: Aug 23 – Oct 25
Safe Start (90%) ✗ May not fit
Transplant: Jun 28 🍅 Harvest: Sep 6 – Nov 8

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 Clark County

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

Soil pH

Your soil pH (6.8–7.8) is within Thyme's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Thyme.

How to Plant Thyme

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

Thyme Water Budget

Plant needs
0.3″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Thyme

Thyme needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Thyme Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 1.3" 1.5" 0" ✅ Rainfall sufficient
Jul 1.3" 1.7" 0" ✅ Rainfall sufficient
Aug 1.3" 2.2" 0" ✅ Rainfall sufficient
Sep 1.3" 1.7" 0" ✅ Rainfall sufficient
Oct 1.8" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Clark County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Thyme 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.

Thyme needs ~920 GDD — county provides 1,092 GDD Good fit

Thyme Planting Timeline — Clark County, ID

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 14 Jun 14 – Jun 28
Harvest August 23 Aug 23 – Oct 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

95 days in Clark County

Growing Tips for Thyme in Clark County

Direct sow Thyme outdoors after June 07 in Clark County when soil has warmed and frost danger has passed.

Your 95.0-day growing season in Clark County is tight for Thyme (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thyme in Clark County, ID?

Clark County is in Zone 5b with an average last frost of June 7. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, ID?

Clark County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 10.

When should I plant Thyme in Clark County, ID?

In Clark County, ID, plant Thyme after the last frost (around June 7) and before the first frost (around September 10). Best results when soil holds above 50°F.

What growing zone is Clark County, ID for Thyme?

Clark County sits in USDA Zone 5b. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.

Can Thyme grow in Clark County's climate?

Yes — Thyme grows well in Clark County's temperate climate. Clark County averages a 95-day frost-free season, with last frost around June 7 and first frost around September 10.

🌱

Your Clark County Garden Planner — Free

A 22-page printable planner built for Clark County (Zone 5b). 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 Clark County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.