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When to plant Thyme in Musselshell County, MT

Musselshell County sits in cold Zone 4b. Plant Thyme May 21–June 4 for the single annual harvest; the September 23 first frost closes the window.

When to Plant Thyme in Musselshell County, MT

Thyme
Musselshell County, Montana Zone 4b July

July in Musselshell County, Montana — your action list

If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 14
Avg. first frost September 23
Soil temp (4") 53°F
Watering High
Pest pressure High
Daylight 15.3 hrs
  1. Collect thyme at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

To set up a strong August, finish these tasks
  • 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.

Musselshell County, Montana is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.

At an elevation of 6,528 feet, Musselshell County receives approximately 15.4 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. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.

Musselshell County, MT (Zone 4b) Short season
132 days
Last Spring Frost May 14
132 growing days
First Fall Frost September 23

Musselshell County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.4

Drainage

Well Drained

Thyme Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 16 🍅 Harvest: Jul 25 – Sep 26
Recommended (50%) ✗ May not fit
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 1 🍅 Harvest: Aug 10 – Oct 12

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 Musselshell County

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

Soil pH

Your soil pH (6.5–8.4) overlaps with Thyme's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Thyme.

How to Plant Thyme

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

Succession Planting Thyme

2
successive plantings in your 132-day season

Sow every 8 weeks. Last sowing by Jun 25 to harvest before frost.

Thyme 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 8/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 1.3" 2" 0" ✅ Rainfall sufficient
Jun 1.3" 1.1" 0.2" 💧 Light watering
Jul 1.3" 1.3" 0" ✅ Rainfall sufficient
Aug 1.3" 1.6" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Musselshell 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 1,518 GDD Excellent fit

Thyme Planting Timeline — Musselshell County, MT

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 21 May 21 – Jun 4
Harvest July 30 Jul 30 – Oct 1

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July Harvest
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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

132 days in Musselshell County

Growing Tips for Thyme in Musselshell County

Direct sow Thyme outdoors after May 14 in Musselshell 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 Musselshell County, MT?

Musselshell County is in Zone 4b with an average last frost of May 14. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Musselshell County, MT?

Musselshell County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 23.

When should I plant Thyme in Musselshell County, MT?

In Musselshell County, MT, plant Thyme after the last frost (around May 14) and before the first frost (around September 23). Best results when soil holds above 50°F.

What growing zone is Musselshell County, MT for Thyme?

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

Can Thyme grow in Musselshell County's climate?

Yes — Thyme grows well in Musselshell County's temperate climate. Musselshell County averages a 132-day frost-free season, with last frost around May 14 and first frost around September 23.

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Your Musselshell County Garden Planner — Free

A 22-page printable planner built for Musselshell County (Zone 4b). 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 Musselshell County, MT. 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.