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When to Plant Lemon Thyme in Madison County, ID

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.

Madison County, Idaho is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 11, giving you a growing season of approximately 103 days.

At an elevation of 6,385 feet, Madison County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Lemon Thyme during the growing season. With low rainfall, drip irrigation is essential for growing Lemon Thyme successfully. Mulch heavily to conserve soil moisture.

Madison County, ID (Zone 5a) Short season
103 days
Last Spring Frost May 31
103 growing days
First Fall Frost September 11

Madison County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 28 🍅 Harvest: Aug 6 – Oct 8
Recommended (50%) ✗ May not fit
Transplant: Jun 7 🍅 Harvest: Aug 16 – Oct 18
Safe Start (90%) ✗ May not fit
Transplant: Jun 28 🍅 Harvest: Sep 6 – Nov 8

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 Madison County

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

Soil pH

Your soil pH (6.2โ€“7.8) is within Lemon Thyme's preferred range (6.0โ€“8.0).

Soil Texture

The loam soil in Madison County is excellent for Lemon Thyme โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). 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
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 1" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 2.1" 0" โ„๏ธ Dormant
May 2.2" 2.5" 0" โœ… Rainfall sufficient
Jun 2.2" 1.2" 1" ๐Ÿ’ง Light watering
Jul 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Aug 2.2" 2.2" 0" โœ… Rainfall sufficient
Sep 2.2" 1.6" 0.6" ๐Ÿ’ง Light watering
Oct โ€” 1.6" 0" โ„๏ธ Dormant
Nov โ€” 1.3" 0" โ„๏ธ Dormant
Dec โ€” 1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Madison County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,100 GDD — county provides 1,416 GDD Good fit

Lemon Thyme Planting Timeline โ€” Madison County, ID

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 7 Jun 7 โ€“ Jun 21
Harvest August 16 Aug 16 โ€“ Oct 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Transplant Outdoors
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

103 days in Madison County

Growing Tips for Lemon Thyme in Madison County

Direct sow Lemon Thyme outdoors after May 31 in Madison County when soil has warmed and frost danger has passed.

Your 103.0-day growing season in Madison County is tight for Lemon Thyme (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Madison County receives only 19" of rain annually. Lemon Thyme needs consistent moisture โ€” 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 Madison County, ID?

Madison County is in Zone 5a with an average last frost of May 31. Plan your Lemon Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Madison County, ID?

Madison County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Madison County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Madison County, ID. Local conditions may vary. Last updated: April 2026.