When to Plant Oregano in Warren County, IA
Top priorities for Warren County, Iowa gardeners in May
Your Warren County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Time to transplant oregano
Frost risk is low now in Warren 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.
Warren County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.
At an elevation of 853 feet, Warren County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Oregano during the growing season.
Warren County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
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 Warren County
How your county's soil matches Oregano's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Oregano's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Warren County is excellent for Oregano — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Oregano will thrive.
How to Plant Oregano
Succession Planting Oregano
Sow every 6.9 weeks. Last sowing by Jul 11 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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | 1.3" | 3.1" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 2.6" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 2.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Warren 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 — Warren County, IA
Oregano Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Harvest | July 5 | Jul 5 – 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
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
166 days in Warren County
Growing Tips for Oregano in Warren County
Direct sow Oregano outdoors after April 26 in Warren 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 Warren County, IA?
Warren County is in Zone 5b with an average last frost of April 26. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.
What planting zone is Warren County, IA?
Warren County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 9.
Your Warren County Garden Planner — Free
A 24-page printable planner built for Warren 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.