Blog

When to Plant Thyme in Adams 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.

Adams County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 6 and the first fall frost is October 5, giving you a growing season of approximately 152 days.

At an elevation of 1,055 feet, Adams County receives approximately 41.5 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.

Adams County, WI (Zone 4b) Moderate season
152 days
Last Spring Frost May 6
152 growing days
First Fall Frost October 5

Adams County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Transplant: May 6 🍅 Harvest: Jul 15 – Sep 16
Recommended (50%) ✓ Fits season (12 days to spare)
Transplant: May 13 🍅 Harvest: Jul 22 – Sep 23
Safe Start (90%) ✓ Fits season (7 days to spare)
Transplant: May 29 🍅 Harvest: Aug 7 – Oct 9

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Thyme needs ~860 GDD — county provides 1,634 GDD Excellent fit

Thyme Planting Timeline โ€” Adams County, WI

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 13 May 13 โ€“ May 27
Harvest July 22 Jul 22 โ€“ Sep 23

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 4b

Growing Season

152 days

Growing Tips for Adams County

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 Adams County, WI?

Adams County is in Zone 4b with an average last frost of May 6. Plan your Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Adams County, WI?

Adams County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 6 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

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