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When to Plant Oregano in Watonwan County, MN

Watonwan County, Minnesota Zone 5a May

What to do in May

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 29
Avg. first frost October 6
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Plant out oregano

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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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.

Watonwan County, Minnesota is in USDA Zone 5a. The average last spring frost is April 29 and the first fall frost is October 6, giving you a growing season of approximately 160 days.

At an elevation of 984 feet, Watonwan County receives approximately 33.9 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.

Watonwan County, MN (Zone 5a) Moderate season
160 days
Last Spring Frost April 29
160 growing days
First Fall Frost October 6
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Watonwan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Transplant: May 1 🍅 Harvest: Jul 3 – Sep 11
Recommended (50%) ✓ Fits season (20 days to spare)
Transplant: May 6 🍅 Harvest: Jul 8 – Sep 16
Safe Start (90%) ✓ Fits season (16 days to spare)
Transplant: May 21 🍅 Harvest: Jul 23 – Oct 1

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 Watonwan County

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

Soil pH

Your soil pH (5.8–7.2) overlaps with Oregano's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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 160-day season

Sow every 6.9 weeks. Last sowing by Jul 08 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.9″/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 1.7" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 1.3" 3.3" 0" ✅ Rainfall sufficient
May 1.3" 3.8" 0" ✅ Rainfall sufficient
Jun 1.3" 4.4" 0" ✅ Rainfall sufficient
Jul 1.3" 3.7" 0" ✅ Rainfall sufficient
Aug 1.3" 3.4" 0" ✅ Rainfall sufficient
Sep 1.3" 3" 0" ✅ Rainfall sufficient
Oct 1.3" 2.9" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Watonwan 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 1,840 GDD Excellent fit

Oregano Planting Timeline — Watonwan County, MN

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 – May 20
Harvest July 8 Jul 8 – Sep 16

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October
November
December
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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 Watonwan County

Growing Tips for Oregano in Watonwan County

Direct sow Oregano outdoors after April 29 in Watonwan 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 Watonwan County, MN?

Watonwan County is in Zone 5a with an average last frost of April 29. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Watonwan County, MN?

Watonwan County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is April 29 and first fall frost is October 6.

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Your Watonwan County Garden Planner — Free

A 24-page printable planner built for Watonwan 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.

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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 Watonwan County, MN. 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.