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When to Plant Napa Cabbage in Yuba County, CA

Yuba County, California Zone 9b May

What to do in May

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

Avg. last frost April 22
Avg. first frost November 9
Soil temp (4") 75°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Sow napa cabbage in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

To set up a strong June, finish these tasks
  • First harvests: 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.

Yuba County, California is in USDA Zone 9b. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.

At an elevation of 303 feet, Yuba County receives approximately 26.5 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Napa Cabbage during the growing season.

Yuba County, CA (Zone 9b) Long season
201 days
Last Spring Frost April 22
201 growing days
First Fall Frost November 9
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Yuba County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (109 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (110 days to spare)
Start indoors: Mar 25 Transplant: Apr 22 🍅 Harvest: Jun 17 – Jul 22
Safe Start (90%) ✓ Fits season (104 days to spare)
Start indoors: Apr 30 Transplant: May 28 🍅 Harvest: Jul 23 – Aug 27

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 Yuba County

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

Soil pH

Your soil pH (6.3–7.3) is within Napa Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Napa Cabbage.

How to Plant Napa Cabbage

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Napa Cabbage

4
successive plantings in your 201-day season

Sow every 6.3 weeks. Last sowing by Aug 26 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,031 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 4.9" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 4.6" 0" ❄️ Dormant
Apr 6.5" 2.2" 4.3" 🚿 Regular watering
May 6.5" 0.7" 5.8" 🚿 Regular watering
Jun 6.5" 0.2" 6.3" 🚿 Regular watering
Jul 6.5" 0" 6.5" 🚿 Regular watering
Aug 6.5" 0" 6.5" 🚿 Regular watering
Sep 6.5" 0.3" 6.2" 🚿 Regular watering
Oct 6.5" 1.1" 5.4" 🚿 Regular watering
Nov 6.5" 2.8" 3.7" 🚿 Regular watering
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Yuba 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 ~1,332 GDD — county provides 4,120 GDD Excellent fit

Napa Cabbage Planting Timeline — Yuba County, CA

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 1 Apr 1 – Apr 22
Harvest June 17 Jun 17 – Jul 22
Fall Sowing September 14 Sep 14 – Sep 28

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

201 days in Yuba County

Growing Tips for Napa Cabbage in Yuba County

Direct sow Napa Cabbage outdoors after April 22 in Yuba 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.

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 Yuba County, CA?

Yuba County is in Zone 9b with an average last frost of April 22. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yuba County, CA?

Yuba County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 22 and first fall frost is November 9.

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Your Yuba County Garden Planner — Free

A 24-page printable planner built for Yuba County (Zone 9b). 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 Yuba County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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