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When to plant Thyme in Weld County, CO

Plant Thyme in Weld County, between May 9 and May 23 — the only viable window. Zone 5b's short season (158 frost-free days) rules out a fall crop.

When to Plant Thyme in Weld County, CO

Thyme

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.

Weld County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 6,992 feet, Weld County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°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.

Weld County, CO (Zone 5b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Weld County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Monthly Watering Guide for Thyme

Thyme needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Thyme Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.7" 2.6" 🚿 Regular watering
Aug 4.3" 1.8" 2.5" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Thyme Planting Timeline — Weld County, CO

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 – May 23
Harvest July 18 Jul 18 – Sep 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

158 days in Weld County

Growing Tips for Weld County

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 Weld County, CO?

Weld County is in Zone 5b with an average last frost of May 2. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Weld County, CO?

Weld County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.

When should I plant Thyme in Weld County, CO?

In Weld County, CO, plant Thyme after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Weld County, CO for Thyme?

Weld 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 Weld County's climate?

Yes — Thyme grows well in Weld County's temperate climate. Weld County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.

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Your Weld County Garden Planner — Free

A 22-page printable planner built for Weld 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 Weld County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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