When to Plant Oregano in Clayton County, IA
Clayton County, Iowa gardeners: here's your May plan
Each item below is timed to Clayton County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Move oregano from tray to bed
Frost risk is low now in Clayton County, Iowa. If you've been covering beds overnight, you can stop.
Oregano is a robust perennial herb essential to Italian and Greek cuisine. Its pungent, savory leaves intensify in flavor when dried.
Clayton County, Iowa is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.
At an elevation of 1,343 feet, Clayton County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Oregano to ensure they mature before fall.
Clayton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.3
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.
Soil Compatibility in Clayton County
How your county's soil matches Oregano's growing requirements.
Soil pH
Your soil pH (5.9–7.3) overlaps with Oregano's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Clayton County is excellent for Oregano — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Oregano.
How to Plant Oregano
Succession Planting Oregano
Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Oregano
Oregano 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 | Oregano Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 2.8" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 2.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Clayton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Oregano 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.
Oregano Planting Timeline — Clayton County, IA
Oregano Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 7 | May 7 – May 21 |
| Harvest | July 9 | Jul 9 – Sep 17 |
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
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
160 days in Clayton County
Growing Tips for Oregano in Clayton County
Direct sow Oregano outdoors after April 30 in Clayton County when soil has warmed and frost danger has passed.
General growing tips
Start from seed, cuttings, or divisions. Harvest just before flowering for strongest flavor. Cut plants back to a few inches in spring to encourage vigorous new growth.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Oregano in Other Locations
Frequently Asked Questions
When should I plant Oregano in Clayton County, IA?
Clayton County is in Zone 5a with an average last frost of April 30. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clayton County, IA?
Clayton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.
Your Clayton County Garden Planner — Free
A 24-page printable planner built for Clayton 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.