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When to Plant Lemon Thyme in Clinton County, IA

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.

Clinton County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 964 feet, Clinton County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Lemon Thyme to ensure they mature before fall.

Clinton County, IA (Zone 5a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Monthly Watering Guide for Lemon Thyme

Lemon 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 Lemon Thyme Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.8" 0" โ„๏ธ Dormant
Mar โ€” 2.9" 0" โ„๏ธ Dormant
Apr 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
May 4.3" 4.8" 0" โœ… Rainfall sufficient
Jun 4.3" 4.5" 0" โœ… Rainfall sufficient
Jul 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Aug 4.3" 4.3" 0" โœ… Rainfall sufficient
Sep 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Oct 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clinton County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Lemon Thyme Planting Timeline โ€” Clinton County, IA

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 24 Apr 24 โ€“ May 8
Harvest July 3 Jul 3 โ€“ Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

Low โ€” drought tolerant

๐Ÿ“… Days to Maturity

70โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

182 days in Clinton County

Growing Tips for Clinton County

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 Clinton County, IA?

Clinton County is in Zone 5a with an average last frost of April 17. Plan your Lemon Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clinton County, IA?

Clinton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clinton 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 Clinton County, IA. Local conditions may vary. Last updated: April 2026.