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When to Plant Marjoram in Morrow County, OR

Sweet marjoram is a tender perennial herb with a delicate, sweet oregano-like flavor. It is a cornerstone of Mediterranean cooking and pairs well with meats and vegetables.

Morrow County, Oregon is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 15, giving you a growing season of approximately 173 days.

At an elevation of 2,335 feet, Morrow County receives approximately 20.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Marjoram during the growing season.

Morrow County, OR (Zone 6a) Moderate season
173 days
Last Spring Frost April 25
173 growing days
First Fall Frost October 15

Morrow County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Recommended (50%) ✓ Fits season (33 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Safe Start (90%) ✓ Fits season (34 days to spare)
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 30

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,464 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Marjoram needs ~1,200 GDD — county provides 2,768 GDD Excellent fit

Marjoram Planting Timeline โ€” Morrow County, OR

Marjoram Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 โ€“ May 16
Harvest July 4 Jul 4 โ€“ Sep 12

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

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

173 days

Growing Tips for Morrow County

Start seeds indoors 6-8 weeks before last frost. Harvest stems just as flower buds appear for peak flavor. In cold climates, grow as an annual or bring containers indoors.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Marjoram in Morrow County, OR?

Morrow County is in Zone 6a with an average last frost of April 25. Plan your Marjoram planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morrow County, OR?

Morrow County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 25 and first fall frost is October 15.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Morrow County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Morrow County, OR. Local conditions may vary. Last updated: April 2026.