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When to Plant Lemon Thyme in Sullivan County, MO

Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

Sullivan County, Missouri is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.

At an elevation of 1,019 feet, Sullivan County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Lemon Thyme to ensure they mature before fall.

Sullivan County, MO (Zone 5b) Moderate season
183 days
Last Spring Frost April 17
183 growing days
First Fall Frost October 17

Sullivan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: Apr 24 🍅 Harvest: Jul 3 – Sep 4
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: May 8 🍅 Harvest: Jul 17 – Sep 18

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
0.8″/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

Lemon Thyme needs ~1,040 GDD — county provides 2,379 GDD Excellent fit

Lemon Thyme Planting Timeline โ€” Sullivan County, MO

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 24 Apr 24 โ€“ May 8
Harvest July 3 Jul 3 โ€“ Sep 4

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
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 5b

Growing Season

183 days

Growing Tips for Sullivan County

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Lemon Thyme in Sullivan County, MO?

Sullivan County is in Zone 5b with an average last frost of April 17. Plan your Lemon Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sullivan County, MO?

Sullivan County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 17.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sullivan County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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 Sullivan County, MO. Local conditions may vary. Last updated: April 2026.