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When to Plant Oregano in Armstrong County, PA

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

Armstrong County, Pennsylvania is in USDA Zone 5b. The average last spring frost is April 29 and the first fall frost is October 18, giving you a growing season of approximately 172 days.

At an elevation of 213 feet, Armstrong County receives approximately 49.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Oregano during the growing season.

Armstrong County, PA (Zone 5b) Moderate season
172 days
Last Spring Frost April 29
172 growing days
First Fall Frost October 18

Armstrong County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Recommended (50%) ✓ Fits season (32 days to spare)
Transplant: May 6 🍅 Harvest: Jul 8 – Sep 16
Safe Start (90%) ✓ Fits season (26 days to spare)
Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7

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 Armstrong County

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

Soil pH

Your soil pH (5.0โ€“6.3) is more acidic than Oregano prefers (6.0โ€“8.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Armstrong County is excellent for Oregano โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Oregano.

How to Plant Oregano

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

Succession Planting Oregano

3
successive plantings in your 172-day season

Sow every 6.9 weeks. Last sowing by Jul 20 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 โ€” 3.6" 0" โ„๏ธ Dormant
Feb โ€” 3.6" 0" โ„๏ธ Dormant
Mar โ€” 4.3" 0" โ„๏ธ Dormant
Apr 1.3" 4.7" 0" โœ… Rainfall sufficient
May 1.3" 5" 0" โœ… Rainfall sufficient
Jun 1.3" 4.7" 0" โœ… Rainfall sufficient
Jul 1.3" 4.4" 0" โœ… Rainfall sufficient
Aug 1.3" 3.9" 0" โœ… Rainfall sufficient
Sep 1.3" 4.6" 0" โœ… Rainfall sufficient
Oct 1.3" 3.7" 0" โœ… Rainfall sufficient
Nov โ€” 3.8" 0" โ„๏ธ Dormant
Dec โ€” 3.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Armstrong County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 2,494 GDD Excellent fit

Oregano Planting Timeline โ€” Armstrong County, PA

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 โ€“ May 20
Harvest July 8 Jul 8 โ€“ Sep 16

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.3"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

172 days in Armstrong County

Growing Tips for Oregano in Armstrong County

Direct sow Oregano outdoors after April 29 in Armstrong 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 Armstrong County, PA?

Armstrong County is in Zone 5b with an average last frost of April 29. Plan your Oregano planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Armstrong County, PA?

Armstrong County, Pennsylvania is in USDA Hardiness Zone 5b. The average last spring frost is April 29 and first fall frost is October 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Armstrong County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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