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When to Plant Oregano in Florence County, WI

Florence County, Wisconsin Zone 4b May

Top priorities for Florence County, Wisconsin gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 26
Avg. first frost September 21
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
June will be here before you know it — start on
  • Transplants going out: 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.

Florence County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.

At an elevation of 1,147 feet, Florence County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Oregano to ensure they mature before fall.

Florence County, WI (Zone 4b) Short season
118 days
Last Spring Frost May 26
118 growing days
First Fall Frost September 21

Florence County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7
Recommended (50%) ✗ May not fit
Transplant: Jun 2 🍅 Harvest: Aug 4 – Oct 13
Safe Start (90%) ✗ May not fit
Transplant: Jun 18 🍅 Harvest: Aug 20 – Oct 29

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 Florence County

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Oregano's range (6.0–8.0), though not a perfect match.

Soil Texture

The silt loam soil in Florence 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

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

Succession Planting Oregano

2
successive plantings in your 118-day season

Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.2″/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 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 1.3" 4.4" 0" ✅ Rainfall sufficient
Jun 1.3" 4.4" 0" ✅ Rainfall sufficient
Jul 1.3" 3.2" 0" ✅ Rainfall sufficient
Aug 1.3" 4" 0" ✅ Rainfall sufficient
Sep 1.3" 2.9" 0" ✅ Rainfall sufficient
Oct 2.7" 0" ❄️ Dormant
Nov 2.4" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Florence 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 ~862 GDD — county provides 1,357 GDD Excellent fit

Oregano Planting Timeline — Florence County, WI

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 – Jun 16
Harvest August 4 Aug 4 – Oct 13

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
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 4b

📆 Growing Season

118 days in Florence County

Growing Tips for Oregano in Florence County

Direct sow Oregano outdoors after May 26 in Florence 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 Florence County, WI?

Florence County is in Zone 4b with an average last frost of May 26. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Florence County, WI?

Florence County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 26 and first fall frost is September 21.

🌱

Your Florence County Garden Planner — Free

A 24-page printable planner built for Florence County (Zone 4b). 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 Florence County, WI. 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.