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When to Plant Lemon Thyme in Lemhi County, ID

Lemhi County, Idaho Zone 5b May

Your May planting checklist for Lemhi County, Idaho

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

Avg. last frost June 9
Avg. first frost September 14
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
Looking ahead to June
  • 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.

Lemhi County, Idaho is in USDA Zone 5b. The average last spring frost is June 9 and the first fall frost is September 14, giving you a growing season of approximately 97 days.

At an elevation of 6,743 feet, Lemhi County receives approximately 12.6 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.

Lemhi County, ID (Zone 5b) Very short season
97 days
Last Spring Frost June 9
97 growing days
First Fall Frost September 14

Lemhi County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

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: Jun 16 🍅 Harvest: Aug 25 – Oct 27
Safe Start (90%) ✗ May not fit
Transplant: Jul 2 🍅 Harvest: Sep 10 – Nov 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 Lemhi County

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

Soil pH

Your soil pH (6.2–8.2) overlaps with Lemon Thyme's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.4" 0" ❄️ Dormant
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.3" 0.9" 💧 Light watering
Sep 2.2" 1.2" 1" 💧 Light watering
Oct 1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Lemhi 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 1,261 GDD Good fit

Lemon Thyme Planting Timeline — Lemhi County, ID

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 16 Jun 16 – Jun 30
Harvest August 25 Aug 25 – Oct 27

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 · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

97 days in Lemhi County

Growing Tips for Lemon Thyme in Lemhi County

Direct sow Lemon Thyme outdoors after June 09 in Lemhi County when soil has warmed and frost danger has passed.

Your 97.0-day growing season in Lemhi County is tight for Lemon Thyme (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Lemhi 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 Lemhi County, ID?

Lemhi County is in Zone 5b with an average last frost of June 9. Plan your Lemon Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lemhi County, ID?

Lemhi County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 9 and first fall frost is September 14.

🌱

Your Lemhi County Garden Planner — Free

A 24-page printable planner built for Lemhi County (Zone 5b). 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 Lemhi County, ID. 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.