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When to Plant Thyme in Union County, TN

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.

Union County, Tennessee is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 29, giving you a growing season of approximately 202 days.

At an elevation of 1,122 feet, Union County receives approximately 50.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Thyme during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Thyme root diseases.

Union County, TN (Zone 7a) Long season
202 days
Last Spring Frost April 10
202 growing days
First Fall Frost October 29

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Transplant: Apr 11 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (62 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 26 – Aug 28
Safe Start (90%) ✓ Fits season (58 days to spare)
Transplant: May 2 🍅 Harvest: Jul 11 – Sep 12

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 Union County

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

Soil pH

Your soil pH (5.8โ€“6.6) overlaps with Thyme's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Thyme.

How to Plant Thyme

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Thyme

3
successive plantings in your 202-day season

Sow every 8 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Thyme needs ~1,280 GDD — county provides 3,232 GDD Excellent fit

Thyme Planting Timeline โ€” Union County, TN

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 17 Apr 17 โ€“ May 1
Harvest June 26 Jun 26 โ€“ Aug 28

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 Harvest
July Harvest
August Harvest
September โ€”
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: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

202 days in Union County

Growing Tips for Thyme in Union County

Direct sow Thyme outdoors after April 10 in Union 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 Union County, TN?

Union County is in Zone 7a with an average last frost of April 10. Plan your Thyme planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, TN?

Union County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 7a 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 Union County, TN. Local conditions may vary. Last updated: April 2026.