Blog

When to plant Thyme in Grand County, CO

Grand County's short 114-day growing season means one Thyme planting between June 4 and June 18. No fall crop in Zone 5a.

When to Plant Thyme in Grand 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.

Grand County, Colorado is in USDA Zone 5a. The average last spring frost is May 28 and the first fall frost is September 19, giving you a growing season of approximately 114 days.

At an elevation of 5,397 feet, Grand County receives approximately 22.2 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.

Grand County, CO (Zone 5a) Short season
114 days
Last Spring Frost May 28
114 growing days
First Fall Frost September 19

Grand County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Thyme Planting Timeline — Grand County, CO

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 – Jun 18
Harvest August 13 Aug 13 – Oct 15

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

Low — drought tolerant

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Grand County

Growing Tips for Grand 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 Grand County, CO?

Grand County is in Zone 5a with an average last frost of May 28. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grand County, CO?

Grand County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 28 and first fall frost is September 19.

When should I plant Thyme in Grand County, CO?

In Grand County, CO, plant Thyme after the last frost (around May 28) and before the first frost (around September 19). Best results when soil holds above 50°F.

What growing zone is Grand County, CO for Thyme?

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

Can Thyme grow in Grand County's climate?

Yes — Thyme grows well in Grand County's temperate climate. Grand County averages a 114-day frost-free season, with last frost around May 28 and first frost around September 19.

🌱

Your Grand County Garden Planner — Free

A 22-page printable planner built for Grand County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grand County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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