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When to Plant Napa Cabbage in Harney County, OR

Harney County, Oregon Zone 6a May

Your May game plan for Harney County, Oregon

Your garden in Harney County, Oregon is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost June 17
Avg. first frost September 6
Soil temp (4") 60°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
Looking ahead to June
  • Transplants going out: napa cabbage
  • Direct-sowing: napa cabbage
  • Fall sowing: napa cabbage

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Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.

Harney County, Oregon is in USDA Zone 6a. The average last spring frost is June 17 and the first fall frost is September 6, giving you a growing season of approximately 81 days.

At an elevation of 679 feet, Harney County receives approximately 22.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Napa Cabbage during the growing season.

Harney County, OR (Zone 6a) Very short season
81 days
Last Spring Frost June 17
81 growing days
First Fall Frost September 6
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Harney County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Aug 7 – Sep 11
Recommended (50%) ✗ May not fit
Start indoors: May 13 Transplant: Jun 17 🍅 Harvest: Aug 12 – Sep 16
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: May 20 Transplant: Jun 24 🍅 Harvest: Aug 19 – Sep 23

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 Harney County

How your county's soil matches Napa Cabbage's growing requirements.

Soil pH

Your soil pH (5.6–6.4) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Harney County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.5%) — Napa Cabbage will thrive.

How to Plant Napa Cabbage

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 306 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Napa Cabbage

Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Napa Cabbage Needs Rainfall You Supplement Action
Jan 3.3" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 6.5" 0.9" 5.6" 🚿 Regular watering
Jul 6.5" 0.4" 6.1" 🚿 Regular watering
Aug 6.5" 0.4" 6.1" 🚿 Regular watering
Sep 6.5" 0.9" 5.6" 🚿 Regular watering
Oct 2" 0" ❄️ Dormant
Nov 3.6" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Harney County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Napa Cabbage 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.

Napa Cabbage needs ~991 GDD — county provides 1,235 GDD Good fit

Napa Cabbage Planting Timeline — Harney County, OR

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors May 13 May 13 – May 27
Transplant Outdoors June 17 Jun 17 – Jul 1
Direct Sow June 3 Jun 3 – Jun 24
Harvest August 12 Aug 12 – Sep 16
Fall Sowing June 28 Jun 28 – Jul 12

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Transplant Outdoors Fall Sowing
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

81 days in Harney County

Growing Tips for Napa Cabbage in Harney County

Direct sow Napa Cabbage outdoors after June 17 in Harney County when soil has warmed and frost danger has passed.

Your 81.0-day growing season in Harney County is tight for Napa Cabbage (55.0-75.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Napa Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Harney County receives only 22" of rain annually. Napa Cabbage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Napa Cabbage in Harney County, OR?

Harney County is in Zone 6a with an average last frost of June 17. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harney County, OR?

Harney County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is June 17 and first fall frost is September 6.

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Your Harney County Garden Planner — Free

A 24-page printable planner built for Harney County (Zone 6a). 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 Harney County, OR. 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.