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When to Plant Oregano in Summit County, CO

Summit County, Colorado Zone 5a May

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Your Summit County, Colorado garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
Coming up in June — start thinking about
  • 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.

Summit County, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°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.

Summit County, CO (Zone 5a) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4

Summit County Soil Profile

Soil Type

Loam

Soil pH

6.8-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Aug 19 – Oct 28
Recommended (50%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Aug 25 – Nov 3
Safe Start (90%) ✗ May not fit
Transplant: Jul 3 🍅 Harvest: Sep 4 – Nov 13

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 Summit County

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

Soil pH

Your soil pH (6.8–8.0) is within Oregano's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Oregano.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Oregano.

How to Plant Oregano

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

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
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 1.4" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 1.8" 0" ❄️ Dormant
Jun 1.3" 1.3" 0" ✅ Rainfall sufficient
Jul 1.3" 1.5" 0" ✅ Rainfall sufficient
Aug 1.3" 1.9" 0" ✅ Rainfall sufficient
Sep 1.3" 1.3" 0" ✅ Rainfall sufficient
Oct 1.6" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Summit 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 ~806 GDD — county provides 860 GDD Good fit

Oregano Planting Timeline — Summit County, CO

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors June 23 Jun 23 – Jul 7
Harvest August 25 Aug 25 – Nov 3

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July Transplant Outdoors
August Harvest
September Harvest
October Harvest
November Harvest
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 5a

📆 Growing Season

80 days in Summit County

Growing Tips for Oregano in Summit County

Direct sow Oregano outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.

Your 80.0-day growing season in Summit County is tight for Oregano (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Summit County, CO?

Summit County is in Zone 5a with an average last frost of June 16. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Summit County, CO?

Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.

🌱

Your Summit County Garden Planner — Free

A 24-page printable planner built for Summit 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 Summit County, CO. 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.