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When to Plant Lemon Thyme in Cass County, MI

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.

Cass County, Michigan is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 17, giving you a growing season of approximately 171 days.

At an elevation of 1,030 feet, Cass County receives approximately 34.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Lemon Thyme during the growing season.

Cass County, MI (Zone 6a) Moderate season
171 days
Last Spring Frost April 29
171 growing days
First Fall Frost October 17

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Transplant: May 3 🍅 Harvest: Jul 12 – Sep 13
Recommended (50%) ✓ Fits season (31 days to spare)
Transplant: May 6 🍅 Harvest: Jul 15 – Sep 16
Safe Start (90%) ✓ Fits season (23 days to spare)
Transplant: May 26 🍅 Harvest: Aug 4 – Oct 6

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.

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
Lemon Thyme needs ~1,160 GDD — county provides 2,479 GDD Excellent fit

Lemon Thyme Planting Timeline โ€” Cass County, MI

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 โ€“ May 20
Harvest July 15 Jul 15 โ€“ Sep 16

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 Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“90 days

Soil pH

6 โ€“ 8

USDA Zone

Zone 6a

Growing Season

171 days

Growing Tips for Cass 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Lemon Thyme in Cass County, MI?

Cass County is in Zone 6a with an average last frost of April 29. Plan your Lemon Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cass County, MI?

Cass County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cass County gardeners in Zone 6a 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 Cass County, MI. Local conditions may vary. Last updated: April 2026.