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When to Plant Lemon Thyme in Sweetwater County, WY

Sweetwater County, Wyoming Zone 5a May

Sweetwater County, Wyoming gardeners: here's your May plan

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Sweetwater County, Wyoming.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 31°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
Before June arrives, get these ready
  • Transplants going out: lemon thyme

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Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

Sweetwater County, Wyoming is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 7,922 feet, Sweetwater County receives approximately 12.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lemon Thyme to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lemon Thyme successfully. Mulch heavily to conserve soil moisture.

Sweetwater County, WY (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20

Sweetwater County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 26 🍅 Harvest: Aug 4 – Oct 6
Recommended (50%) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Aug 14 – Oct 16
Safe Start (90%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Sep 1 – Nov 3

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 Sweetwater County

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

Soil pH

Your soil pH (6.2–7.7) is within Lemon Thyme's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Lemon Thyme.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Lemon Thyme.

How to Plant Lemon Thyme

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

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 213 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lemon Thyme

Lemon Thyme needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Lemon Thyme Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.2" 1.5" 0.7" 💧 Light watering
Jun 2.2" 1" 1.2" 🚿 Regular watering
Jul 2.2" 1.1" 1.1" 🚿 Regular watering
Aug 2.2" 1.3" 0.9" 💧 Light watering
Sep 2.2" 1" 1.2" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Lemon 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.

Lemon Thyme needs ~1,040 GDD — county provides 1,482 GDD Excellent fit

Lemon Thyme Planting Timeline — Sweetwater County, WY

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 5 Jun 5 – Jun 19
Harvest August 14 Aug 14 – Oct 16

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

0.5"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Sweetwater County

Growing Tips for Lemon Thyme in Sweetwater County

Direct sow Lemon Thyme outdoors after May 29 in Sweetwater County when soil has warmed and frost danger has passed.

Sweetwater County receives only 13" of rain annually. Lemon Thyme needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Thyme in Sweetwater County, WY?

Sweetwater County is in Zone 5a with an average last frost of May 29. Plan your Lemon Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sweetwater County, WY?

Sweetwater County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

🌱

Your Sweetwater County Garden Planner — Free

A 24-page printable planner built for Sweetwater 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 Sweetwater 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.