When to plant Thyme in Yellowstone County, MT
Yellowstone County's 147-day season only supports one Thyme planting per year. Sow between May 16 and May 30 for the best chance at full maturity before October 3.
When to Plant Thyme in Yellowstone County, MT
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.
Yellowstone County, Montana is in USDA Zone 5a. The average last spring frost is May 9 and the first fall frost is October 3, giving you a growing season of approximately 147 days.
At an elevation of 7,432 feet, Yellowstone County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Thyme to ensure they mature before fall.
Yellowstone County Soil Profile
Soil Type
Loam
Soil pH
6.2-8
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Jun | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Jul | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Aug | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Nov | — | 1.6" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Yellowstone County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Thyme Planting Timeline — Yellowstone County, MT
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Harvest | July 25 | Jul 25 – Sep 26 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 5a
📆 Growing Season
147 days in Yellowstone County
Growing Tips for Yellowstone 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 →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Yellowstone County, MT?
Yellowstone County is in Zone 5a with an average last frost of May 9. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yellowstone County, MT?
Yellowstone County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 9 and first fall frost is October 3.
When should I plant Thyme in Yellowstone County, MT?
In Yellowstone County, MT, plant Thyme after the last frost (around May 9) and before the first frost (around October 3). Best results when soil holds above 50°F.
What growing zone is Yellowstone County, MT for Thyme?
Yellowstone 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 Yellowstone County's climate?
Yes — Thyme grows well in Yellowstone County's temperate climate. Yellowstone County averages a 147-day frost-free season, with last frost around May 9 and first frost around October 3.
Your Yellowstone County Garden Planner — Free
A 22-page printable planner built for Yellowstone 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.