When to Plant Marjoram in Clackamas 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.
Clackamas County, Oregon is in USDA Zone 8a. The average last spring frost is April 14 and the first fall frost is October 28, giving you a growing season of approximately 197 days.
At an elevation of 199 feet, Clackamas County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Marjoram during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Marjoram root diseases.
Clackamas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.3
Drainage
Well Drained
Plant Planting Risk Windows
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 Clackamas County
How your county's soil matches Marjoram's growing requirements.
Soil pH
Your soil pH (5.7–6.3) is more acidic than Marjoram prefers (6.5–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Clackamas County is excellent for Marjoram — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.7%) — Marjoram will thrive.
How to Plant Marjoram
Succession Planting Marjoram
Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Marjoram
Marjoram 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 | Marjoram Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 8.3" | 0" | ❄️ Dormant |
| Feb | — | 5.3" | 0" | ❄️ Dormant |
| Mar | — | 4.8" | 0" | ❄️ Dormant |
| Apr | 1.3" | 4" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 2.1" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 0.8" | 0.5" | 💧 Light watering |
| Aug | 1.3" | 1" | 0.3" | 💧 Light watering |
| Sep | 1.3" | 2.2" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 8.2" | 0" | ❄️ Dormant |
| Dec | — | 8.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Clackamas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Marjoram 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.
Marjoram Planting Timeline — Clackamas County, OR
Marjoram Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Harvest | June 23 | Jun 23 – Sep 1 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| 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 6.5–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
197 days in Clackamas County
Growing Tips for Marjoram in Clackamas County
Direct sow Marjoram outdoors after April 14 in Clackamas County when soil has warmed and frost danger has passed.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Marjoram in Other Locations
Frequently Asked Questions
When should I plant Marjoram in Clackamas County, OR?
Clackamas County is in Zone 8a with an average last frost of April 14. Plan your Marjoram planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clackamas County, OR?
Clackamas County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 14 and first fall frost is October 28.
Plan Your Garden with Confidence
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