Blog

When to Plant Oregano in Ravalli County, MT

Ravalli County, Montana Zone 5a April

Top priorities for Ravalli County, Montana gardeners in April

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Ravalli County, Montana.

Avg. last frost May 21
Avg. first frost September 20
Soil temp (4") 20°F
Watering High
Pest pressure Low
Daylight 13.3 hrs
May will be here before you know it — start on
  • Transplants going out: oregano

Instant PDF download. No spam, unsubscribe any time.

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

Ravalli County, Montana is in USDA Zone 5a. The average last spring frost is May 21 and the first fall frost is September 20, giving you a growing season of approximately 122 days.

At an elevation of 7,813 feet, Ravalli County receives approximately 15.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Oregano to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Oregano successfully. Mulch heavily to conserve soil moisture.

Ravalli County, MT (Zone 5a) Short season
122 days
Last Spring Frost May 21
122 growing days
First Fall Frost September 20
Share this guide:

Ravalli County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29
Recommended (50%) ✗ May not fit
Transplant: May 28 🍅 Harvest: Jul 30 – Oct 8
Safe Start (90%) ✗ May not fit
Transplant: Jun 16 🍅 Harvest: Aug 18 – Oct 27

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 Ravalli County

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

Soil pH

Your soil pH (6.5–7.8) is within Oregano's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Oregano.

How to Plant Oregano

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

Succession Planting Oregano

2
successive plantings in your 122-day season

Sow every 6.9 weeks. Last sowing by Jun 22 to harvest before frost.

Plant Water Budget

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

Water stress score is 8/10 — 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 1.1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 1.3" 1.8" 0" ✅ Rainfall sufficient
Jun 1.3" 0.9" 0.4" 💧 Light watering
Jul 1.3" 1.5" 0" ✅ Rainfall sufficient
Aug 1.3" 1.6" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Ravalli 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 ~975 GDD — county provides 1,586 GDD Excellent fit

Oregano Planting Timeline — Ravalli County, MT

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors May 28 May 28 – Jun 11
Harvest July 30 Jul 30 – Oct 8

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July Harvest
August Harvest
September Harvest
October Harvest
November
December
Share this guide:

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 5a

📆 Growing Season

122 days in Ravalli County

Growing Tips for Oregano in Ravalli County

Direct sow Oregano outdoors after May 21 in Ravalli 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 Ravalli County, MT?

Ravalli County is in Zone 5a with an average last frost of May 21. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ravalli County, MT?

Ravalli County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 21 and first fall frost is September 20.

🌱

Your Ravalli County Garden Planner — Free

A 24-page printable planner built for Ravalli 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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