When to plant Thyme in Dallas County, IA
In Dallas County, Thyme is a single-season spring crop — there's no second fall window. Plant May 1–May 15 for an 70–90-day harvest, finishing well before the October 9 first frost.
When to Plant Thyme in Dallas 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.
Dallas County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 9, giving you a growing season of approximately 168 days.
At an elevation of 693 feet, Dallas County receives approximately 37.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Thyme during the growing season.
Dallas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7
Drainage
Well Drained
Monthly Watering Guide for Thyme
Thyme needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Thyme Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| May | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Dallas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Thyme Planting Timeline — Dallas County, IA
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Harvest | July 10 | Jul 10 – Sep 11 |
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
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
168 days in Dallas County
Growing Tips for Dallas 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 →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Dallas County, IA?
Dallas County is in Zone 5b with an average last frost of April 24. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Dallas County, IA?
Dallas County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 9.
When should I plant Thyme in Dallas County, IA?
In Dallas County, IA, plant Thyme after the last frost (around April 24) and before the first frost (around October 9). Best results when soil holds above 50°F.
What growing zone is Dallas County, IA for Thyme?
Dallas County sits in USDA Zone 5b. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.
Can Thyme grow in Dallas County's climate?
Yes — Thyme grows well in Dallas County's temperate climate. Dallas County averages a 168-day frost-free season, with last frost around April 24 and first frost around October 9.
Your Dallas County Garden Planner — Free
A 22-page printable planner built for Dallas County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.