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When to Plant Thyme in Sheridan County, WY

Sheridan County, Wyoming Zone 5a May

Your May planting checklist for Sheridan County, Wyoming

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

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Transplant thyme outside

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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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.

Sheridan County, Wyoming is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 5,266 feet, Sheridan County receives approximately 14.7 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.

Sheridan County, WY (Zone 5a) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20
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Sheridan County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1
Recommended (50%) ✗ May not fit
Transplant: May 27 🍅 Harvest: Aug 5 – Oct 7
Safe Start (90%) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Aug 26 – Oct 28

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 Sheridan County

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

Soil pH

Your soil pH (6.6–7.8) is within Thyme's preferred range (6.0–8.0).

Soil Texture

The loam soil in Sheridan 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 (2.6%). 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 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 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 1.3" 1.9" 0" ✅ Rainfall sufficient
Jun 1.3" 1" 0.3" 💧 Light watering
Jul 1.3" 1.1" 0.2" 💧 Light watering
Aug 1.3" 1.7" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1.2" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Sheridan 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 1,414 GDD Excellent fit

Thyme Planting Timeline — Sheridan County, WY

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 27 May 27 – Jun 10
Harvest August 5 Aug 5 – Oct 7

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
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: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Sheridan County

Growing Tips for Thyme in Sheridan County

Direct sow Thyme outdoors after May 20 in Sheridan 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 Sheridan County, WY?

Sheridan County is in Zone 5a with an average last frost of May 20. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sheridan County, WY?

Sheridan County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 20.

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Your Sheridan County Garden Planner — Free

A 24-page printable planner built for Sheridan 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.

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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 Sheridan County, WY. 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.