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When to Plant Thyme in Grant 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.

Grant County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 8, giving you a growing season of approximately 163 days.

At an elevation of 884 feet, Grant County receives approximately 37.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Thyme to ensure they mature before fall.

Grant County, WI (Zone 4b) Moderate season
163 days
Last Spring Frost April 28
163 growing days
First Fall Frost October 8

Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (23 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 10
Recommended (50%) ✓ Fits season (23 days to spare)
Transplant: May 5 🍅 Harvest: Jul 14 – Sep 15
Safe Start (90%) ✓ Fits season (17 days to spare)
Transplant: May 22 🍅 Harvest: Jul 31 – Oct 2

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 Grant County

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

Soil pH

Your soil pH (6.1โ€“7.1) is within Thyme's preferred range (6.0โ€“8.0).

Soil Texture

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

Drainage

Drainage is adequate for Thyme.

Organic Matter

Organic matter is excellent (5.1%) 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 163-day season

Sow every 8 weeks. Last sowing by Jul 10 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Thyme needs ~860 GDD — county provides 1,752 GDD Excellent fit

Thyme Planting Timeline โ€” Grant County, WI

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 โ€“ May 19
Harvest July 14 Jul 14 โ€“ Sep 15

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

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: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

163 days in Grant County

Growing Tips for Thyme in Grant County

Direct sow Thyme outdoors after April 28 in Grant 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 Grant County, WI?

Grant County is in Zone 4b with an average last frost of April 28. Plan your Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grant County, WI?

Grant County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grant County gardeners in Zone 4b 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 Grant County, WI. Local conditions may vary. Last updated: April 2026.