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When to plant Thyme in Howard County, IA

In Howard County, Thyme is a spring-only crop. Plant May 11–May 25 once soil hits 50°F.

When to Plant Thyme in Howard County, IA

Thyme

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.

Howard County, Iowa is in USDA Zone 4b. The average last spring frost is May 4 and the first fall frost is October 5, giving you a growing season of approximately 154 days.

At an elevation of 1,297 feet, Howard County receives approximately 39.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Thyme to ensure they mature before fall.

Howard County, IA (Zone 4b) Moderate season
154 days
Last Spring Frost May 4
154 growing days
First Fall Frost October 5

Howard County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Thyme Planting Timeline — Howard County, IA

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 11 May 11 – May 25
Harvest July 20 Jul 20 – Sep 21

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: N/A

🗺️ USDA Zone

Zone 4b

📆 Growing Season

154 days in Howard County

Growing Tips for Howard 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thyme in Howard County, IA?

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

What planting zone is Howard County, IA?

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

When should I plant Thyme in Howard County, IA?

In Howard County, IA, plant Thyme after the last frost (around May 4) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Howard County, IA for Thyme?

Howard County sits in USDA Zone 4b. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.

Can Thyme grow in Howard County's climate?

Yes — Thyme grows well in Howard County's temperate climate. Howard County averages a 154-day frost-free season, with last frost around May 4 and first frost around October 5.

🌱

Your Howard County Garden Planner — Free

A 22-page printable planner built for Howard County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Howard County, IA. Local conditions may vary. Last updated: July 2026.

Sources & credits

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