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When to plant Thyme in St. Louis County, MO

Plant Thyme in St. Louis County, between April 20 and May 4 — the only viable window. Zone 7a's short season (194 frost-free days) rules out a fall crop.

When to Plant Thyme in St. Louis County, MO

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.

St. Louis County, Missouri is in USDA Zone 7a. The average last spring frost is April 13 and the first fall frost is October 24, giving you a growing season of approximately 194 days.

At an elevation of 895 feet, St. Louis County receives approximately 40.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Thyme during the growing season.

St. Louis County, MO (Zone 7a) Moderate season
194 days
Last Spring Frost April 13
194 growing days
First Fall Frost October 24

St. Louis County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Thyme Planting Timeline — St. Louis County, MO

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 20 Apr 20 – May 4
Harvest June 29 Jun 29 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June Harvest
July Harvest
August Harvest
September
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 7a

📆 Growing Season

194 days in St. Louis County

Growing Tips for St. Louis 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 St. Louis County, MO?

St. Louis County is in Zone 7a with an average last frost of April 13. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Louis County, MO?

St. Louis County, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is April 13 and first fall frost is October 24.

When should I plant Thyme in St. Louis County, MO?

In St. Louis County, MO, plant Thyme after the last frost (around April 13) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is St. Louis County, MO for Thyme?

St. Louis County sits in USDA Zone 7a. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.

Can Thyme grow in St. Louis County's climate?

Yes — Thyme grows well in St. Louis County's temperate climate. St. Louis County averages a 194-day frost-free season, with last frost around April 13 and first frost around October 24.

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Your St. Louis County Garden Planner — Free

A 22-page printable planner built for St. Louis County (Zone 7a). 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 St. Louis County, MO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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