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When to Plant Napa Cabbage in Sherman County, OR

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.

Sherman County, Oregon is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 862 feet, Sherman County receives approximately 15 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Napa Cabbage during the growing season. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.

Sherman County, OR (Zone 6a) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Sherman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (96 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: Jun 2 – Jul 7
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 9 – Jul 14
Safe Start (90%) ✓ Fits season (93 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 1

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 Sherman County

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

Soil pH

Your soil pH (5.7โ€“6.3) overlaps with Napa Cabbage's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) โ€” 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.

Succession Planting Napa Cabbage

3
successive plantings in your 186-day season

Sow every 6.3 weeks. Last sowing by Aug 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,922 gal / 100 sq ft

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 โ€” 2.2" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 1.5" 0" โ„๏ธ Dormant
Apr 6.5" 1.2" 5.3" ๐Ÿšฟ Regular watering
May 6.5" 0.8" 5.7" ๐Ÿšฟ Regular watering
Jun 6.5" 0.5" 6" ๐Ÿšฟ Regular watering
Jul 6.5" 0.2" 6.3" ๐Ÿšฟ Regular watering
Aug 6.5" 0.3" 6.2" ๐Ÿšฟ Regular watering
Sep 6.5" 0.5" 6" ๐Ÿšฟ Regular watering
Oct 6.5" 1.3" 5.2" ๐Ÿšฟ Regular watering
Nov โ€” 2.4" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Sherman County). Supplement amounts are based on average rainfall โ€” 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" 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.

Napa Cabbage needs ~1,089 GDD — county provides 3,115 GDD Excellent fit

Napa Cabbage Planting Timeline โ€” Sherman County, OR

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 14 Apr 14 โ€“ Apr 28
Direct Sow March 31 Mar 31 โ€“ Apr 21
Harvest June 9 Jun 9 โ€“ Jul 14
Fall Sowing August 8 Aug 8 โ€“ Aug 22

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1.5"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

55โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

186 days in Sherman County

Growing Tips for Napa Cabbage in Sherman County

Direct sow Napa Cabbage outdoors after April 14 in Sherman County when soil has warmed and frost danger has passed.

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.

Sherman County receives only 15" of rain annually. Napa Cabbage needs consistent moisture โ€” 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 Sherman County, OR?

Sherman County is in Zone 6a with an average last frost of April 14. Plan your Napa Cabbage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sherman County, OR?

Sherman County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sherman 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 Sherman County, OR. Local conditions may vary. Last updated: April 2026.