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When to plant Oregano in McLean County, IL

McLean County's short 183-day growing season means one Oregano planting between April 25 and May 9. No fall crop in Zone 6a.

When to Plant Oregano in McLean County, IL

Oregano
McLean County, Illinois Zone 6a August

August in McLean County, Illinois — your action list

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Avg. last frost April 18
Avg. first frost October 18
Soil temp (4") 77°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. It's harvest week for oregano

    If you can't use it all right away, check the food-preservation section of your planner.

September will be here before you know it — start on
  • 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.

McLean County, Illinois is in USDA Zone 6a. The average last spring frost is April 18 and the first fall frost is October 18, giving you a growing season of approximately 183 days.

At an elevation of 1,024 feet, McLean County receives approximately 31.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Oregano during the growing season.

McLean County, IL (Zone 6a) Moderate season
183 days
Last Spring Frost April 18
183 growing days
First Fall Frost October 18

McLean County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Oregano Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19

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 McLean County

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

Soil pH

Your soil pH (6.0–7.0) is within Oregano's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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 183-day season

Sow every 6.9 weeks. Last sowing by Jul 20 to harvest before frost.

Oregano Water Budget

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

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 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 1.3" 2.9" 0" ✅ Rainfall sufficient
May 1.3" 4" 0" ✅ Rainfall sufficient
Jun 1.3" 3.8" 0" ✅ Rainfall sufficient
Jul 1.3" 3.5" 0" ✅ Rainfall sufficient
Aug 1.3" 3.2" 0" ✅ Rainfall sufficient
Sep 1.3" 2.7" 0" ✅ Rainfall sufficient
Oct 1.3" 2.8" 0" ✅ Rainfall sufficient
Nov 2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in McLean 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 ~1,088 GDD — county provides 2,653 GDD Excellent fit

Oregano Planting Timeline — McLean County, IL

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors April 25 Apr 25 – May 9
Harvest June 27 Jun 27 – Sep 5

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

183 days in McLean County

Growing Tips for Oregano in McLean County

Direct sow Oregano outdoors after April 18 in McLean 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 McLean County, IL?

McLean County is in Zone 6a with an average last frost of April 18. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is McLean County, IL?

McLean County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 18 and first fall frost is October 18.

When should I plant Oregano in McLean County, IL?

In McLean County, IL, plant Oregano after the last frost (around April 18) and before the first frost (around October 18). Best results when soil holds above 50°F.

What growing zone is McLean County, IL for Oregano?

McLean County sits in USDA Zone 6a. Oregano grows reliably in zones 4a through 10b, so it's a good fit here.

Can Oregano grow in McLean County's climate?

Yes — Oregano grows well in McLean County's temperate climate. McLean County averages a 183-day frost-free season, with last frost around April 18 and first frost around October 18.

🌱

Your McLean County Garden Planner — Free

A 22-page printable planner built for McLean 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 McLean County, IL. Local conditions may vary. Last updated: August 2026.

Sources & credits

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