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When to Plant Thyme in Moffat County, CO

Moffat County, Colorado Zone 5b May

Moffat County, Colorado gardeners: here's your May plan

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

Avg. last frost June 7
Avg. first frost September 14
Soil temp (4") 39°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: 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.

Moffat County, Colorado is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 14, giving you a growing season of approximately 99 days.

At an elevation of 6,597 feet, Moffat County receives approximately 12.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°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.

Moffat County, CO (Zone 5b) Very short season
99 days
Last Spring Frost June 7
99 growing days
First Fall Frost September 14
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Moffat County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 15
Recommended (50%) ✗ May not fit
Transplant: Jun 14 🍅 Harvest: Aug 23 – Oct 25
Safe Start (90%) ✗ May not fit
Transplant: Jun 27 🍅 Harvest: Sep 5 – Nov 7

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 Moffat County

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

Soil pH

Your soil pH (6.8–8.3) overlaps with Thyme's range (6.0–8.0), though not a perfect match.

Soil Texture

The loam soil in Moffat 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

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.5″/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" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 1.3" 0.8" 0.5" 💧 Light watering
Jul 1.3" 1" 0.3" 💧 Light watering
Aug 1.3" 1.4" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Moffat 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 ~1,160 GDD — county provides 1,435 GDD Good fit

Thyme Planting Timeline — Moffat County, CO

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
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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: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

99 days in Moffat County

Growing Tips for Thyme in Moffat County

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

Your 99.0-day growing season in Moffat 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 Moffat County, CO?

Moffat 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 Moffat County, CO?

Moffat County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 14.

🌱

Your Moffat County Garden Planner — Free

A 24-page printable planner built for Moffat 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 Moffat County, CO. 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.