When to Plant Thyme in Monroe County, IA
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.
Monroe County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.
At an elevation of 968 feet, Monroe County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Thyme during the growing season.
Monroe County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.3
Drainage
Well Drained
Plant Planting Risk Windows
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
Thyme Planting Timeline — Monroe County, IA
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Harvest | July 12 | Jul 12 – Sep 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
6 – 8
USDA Zone
Zone 5a
Growing Season
170 days
Growing Tips for Monroe 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
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Monroe County, IA?
Monroe County is in Zone 5a with an average last frost of April 26. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Monroe County, IA?
Monroe County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 13.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Monroe County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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