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When to Plant Thyme in Washington County, UT

Washington County, Utah Zone 8b May

This month in Washington County, Utah

Each item below is timed to Washington County, Utah's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 6
Avg. first frost November 1
Soil temp (4") 62°F
Watering High
Pest pressure High
Daylight 14 hrs
Coming up in June — start thinking about
  • First harvests: thyme

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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.

Washington County, Utah is in USDA Zone 8b. The average last spring frost is April 6 and the first fall frost is November 1, giving you a growing season of approximately 209 days.

At an elevation of 3,524 feet, Washington County receives approximately 12.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Thyme during the growing season. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.

Washington County, UT (Zone 8b) Long season
209 days
Last Spring Frost April 6
209 growing days
First Fall Frost November 1
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Washington County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (77 days to spare)
Transplant: Mar 20 🍅 Harvest: May 29 – Jul 31
Recommended (50%) ✓ Fits season (69 days to spare)
Transplant: Apr 13 🍅 Harvest: Jun 22 – Aug 24
Safe Start (90%) ✓ Fits season (38 days to spare)
Transplant: Jun 3 🍅 Harvest: Aug 12 – Oct 14

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 Washington County

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

Soil pH

Your soil pH (6.7–8.0) is within Thyme's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Thyme.

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

Succession Planting Thyme

3
successive plantings in your 209-day season

Sow every 8 weeks. Last sowing by Aug 03 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 301 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.3" 1.2" 0.1" 💧 Light watering
May 1.3" 1.4" 0" ✅ Rainfall sufficient
Jun 1.3" 0.9" 0.4" 💧 Light watering
Jul 1.3" 1.2" 0.1" 💧 Light watering
Aug 1.3" 1.4" 0" ✅ Rainfall sufficient
Sep 1.3" 0.9" 0.4" 💧 Light watering
Oct 1.3" 1.2" 0.1" 💧 Light watering
Nov 1.3" 1" 0.3" 💧 Light watering
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Washington 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 ~1,400 GDD — county provides 3,657 GDD Excellent fit

Thyme Planting Timeline — Washington County, UT

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 13 Apr 13 – Apr 27
Harvest June 22 Jun 22 – Aug 24

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 8b

📆 Growing Season

209 days in Washington County

Growing Tips for Thyme in Washington County

Direct sow Thyme outdoors after April 06 in Washington County when soil has warmed and frost danger has passed.

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 Washington County, UT?

Washington County is in Zone 8b with an average last frost of April 6. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, UT?

Washington County, Utah is in USDA Hardiness Zone 8b. The average last spring frost is April 6 and first fall frost is November 1.

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Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 8b). 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 Washington County, UT. 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.