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When to Plant Thyme in Florence County, WI

Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.

Florence County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.

At an elevation of 1,147 feet, Florence County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Thyme to ensure they mature before fall.

Florence County, WI (Zone 4a) Short season
118 days
Last Spring Frost May 26
118 growing days
First Fall Frost September 21

Florence County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 27 🍅 Harvest: Aug 5 – Oct 7
Recommended (50%) ✗ May not fit
Transplant: Jun 2 🍅 Harvest: Aug 11 – Oct 13
Safe Start (90%) ✗ May not fit
Transplant: Jun 18 🍅 Harvest: Aug 27 – Oct 29

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 Florence County

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

Soil pH

Your soil pH (5.8โ€“6.8) overlaps with Thyme's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) โ€” Thyme will thrive.

How to Plant Thyme

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

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Thyme needs ~920 GDD — county provides 1,357 GDD Excellent fit

Thyme Planting Timeline โ€” Florence County, WI

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 โ€“ Jun 16
Harvest August 11 Aug 11 โ€“ Oct 13

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

0.3"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

118 days in Florence County

Growing Tips for Thyme in Florence County

Direct sow Thyme outdoors after May 26 in Florence County when soil has warmed and frost danger has passed.

General growing tips

Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Thyme in Florence County, WI?

Florence County is in Zone 4a with an average last frost of May 26. Plan your Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Florence County, WI?

Florence County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 26 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Florence County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Florence County, WI. Local conditions may vary. Last updated: April 2026.