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When to Plant Oregano in Vermilion County, IL

Vermilion County, Illinois Zone 6a May

Vermilion County, Illinois gardeners: here's your May plan

Each item below is timed to Vermilion County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 14
Avg. first frost October 16
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
A few tasks this May that'll pay off in June
  • First harvests: oregano

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Oregano is a robust perennial herb essential to Italian and Greek cuisine. Its pungent, savory leaves intensify in flavor when dried.

Vermilion County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 16, giving you a growing season of approximately 185 days.

At an elevation of 1,218 feet, Vermilion County receives approximately 31.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Oregano during the growing season.

Vermilion County, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 14
185 growing days
First Fall Frost October 16

Vermilion County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 29
Recommended (50%) ✓ Fits season (45 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Safe Start (90%) ✓ Fits season (40 days to spare)
Transplant: May 10 🍅 Harvest: Jul 12 – Sep 20

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 Vermilion County

How your county's soil matches Oregano's growing requirements.

Soil pH

Your soil pH (6.2–6.9) is within Oregano's preferred range (6.0–8.0).

Soil Texture

The silt loam soil in Vermilion County is excellent for Oregano — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.2%) — Oregano will thrive.

How to Plant Oregano

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Oregano

3
successive plantings in your 185-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 1.3" 3.1" 0" ✅ Rainfall sufficient
May 1.3" 3.9" 0" ✅ Rainfall sufficient
Jun 1.3" 3.7" 0" ✅ Rainfall sufficient
Jul 1.3" 3.8" 0" ✅ Rainfall sufficient
Aug 1.3" 3.5" 0" ✅ Rainfall sufficient
Sep 1.3" 2.5" 0" ✅ Rainfall sufficient
Oct 1.3" 2.1" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Vermilion 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 needs ~1,031 GDD — county provides 2,543 GDD Excellent fit

Oregano Planting Timeline — Vermilion County, IL

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors April 21 Apr 21 – May 5
Harvest June 23 Jun 23 – Sep 1

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June Harvest
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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

185 days in Vermilion County

Growing Tips for Oregano in Vermilion County

Direct sow Oregano outdoors after April 14 in Vermilion 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 →

Frequently Asked Questions

When should I plant Oregano in Vermilion County, IL?

Vermilion County is in Zone 6a with an average last frost of April 14. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Vermilion County, IL?

Vermilion County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 16.

🌱

Your Vermilion County Garden Planner — Free

A 24-page printable planner built for Vermilion County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Vermilion County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.