When to plant Thyme in Guthrie County, IA
Plant Thyme in Guthrie County, between May 3 and May 17 — the only viable window. Zone 5a's short season (163 frost-free days) rules out a fall crop.
When to Plant Thyme in Guthrie County, IA
July in the garden — Guthrie County, Iowa
If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.
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It's harvest week for thyme
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Looking ahead to August
- First harvests: 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.
Guthrie County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 6, giving you a growing season of approximately 163 days.
At an elevation of 1,378 feet, Guthrie County receives approximately 31.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Thyme to ensure they mature before fall.
Guthrie County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
Drainage
Well Drained
Thyme 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.
Soil Compatibility in Guthrie County
How your county's soil matches Thyme's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Thyme's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Guthrie County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Thyme will thrive.
How to Plant Thyme
Succession Planting Thyme
Sow every 8 weeks. Last sowing by Jul 08 to harvest before frost.
Thyme Water Budget
Monthly Watering Guide for Thyme
Thyme needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.
| Month | Thyme Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 1.3" | 3.1" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 2.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Guthrie County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Thyme Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Thyme Planting Timeline — Guthrie 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
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
163 days in Guthrie County
Growing Tips for Thyme in Guthrie County
Direct sow Thyme outdoors after April 26 in Guthrie 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
Check more plant combinations with our Companion Planting Checker →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Guthrie County, IA?
Guthrie 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 Guthrie County, IA?
Guthrie County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 6.
When should I plant Thyme in Guthrie County, IA?
In Guthrie County, IA, plant Thyme after the last frost (around April 26) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Guthrie County, IA for Thyme?
Guthrie County sits in USDA Zone 5a. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.
Can Thyme grow in Guthrie County's climate?
Yes — Thyme grows well in Guthrie County's temperate climate. Guthrie County averages a 163-day frost-free season, with last frost around April 26 and first frost around October 6.
Your Guthrie County Garden Planner — Free
A 22-page printable planner built for Guthrie County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.