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When to Plant Thyme in Barron 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.

Barron County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 25, giving you a growing season of approximately 131 days.

At an elevation of 1,256 feet, Barron County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Thyme to ensure they mature before fall.

Barron County, WI (Zone 4a) Short season
131 days
Last Spring Frost May 17
131 growing days
First Fall Frost September 25

Barron County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7

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: May 24 🍅 Harvest: Aug 2 – Oct 4
Safe Start (90%) ✗ May not fit
Transplant: Jun 8 🍅 Harvest: Aug 17 – Oct 19

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 Barron County

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

Soil pH

Your soil pH (5.8โ€“7.0) overlaps with Thyme's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) โ€” Thyme will thrive.

How to Plant Thyme

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

Succession Planting Thyme

2
successive plantings in your 131-day season

Sow every 8 weeks. Last sowing by Jun 27 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Thyme

Thyme needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Thyme Needs Rainfall You Supplement Action
Jan โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 4.3" 0" โ„๏ธ Dormant
May 1.3" 4.6" 0" โœ… Rainfall sufficient
Jun 1.3" 5.6" 0" โœ… Rainfall sufficient
Jul 1.3" 3.9" 0" โœ… Rainfall sufficient
Aug 1.3" 4" 0" โœ… Rainfall sufficient
Sep 1.3" 3.3" 0" โœ… Rainfall sufficient
Oct โ€” 3" 0" โ„๏ธ Dormant
Nov โ€” 3.2" 0" โ„๏ธ Dormant
Dec โ€” 2.5" 0" โ„๏ธ Dormant

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

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.

Thyme needs ~980 GDD — county provides 1,604 GDD Excellent fit

Thyme Planting Timeline โ€” Barron County, WI

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 24 May 24 โ€“ Jun 7
Harvest August 2 Aug 2 โ€“ Oct 4

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 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

131 days in Barron County

Growing Tips for Thyme in Barron County

Direct sow Thyme outdoors after May 17 in Barron 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thyme in Barron County, WI?

Barron County is in Zone 4a with an average last frost of May 17. Plan your Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Barron County, WI?

Barron County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 25.

๐ŸŒฑ

Plan Your Garden with Confidence

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