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When to Plant Chinese Cabbage in Napa County, CA

Napa County, California Zone 9b May

This month in Napa County, California

Each item below is timed to Napa County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 74°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Pick chinese cabbage

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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Chinese cabbage (Napa cabbage) forms elongated, barrel-shaped heads with tender, mild-flavored leaves. It is a staple in Asian cooking, particularly for kimchi.

Napa County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.

At an elevation of 449 feet, Napa County receives approximately 35 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Chinese Cabbage during the growing season.

Napa County, CA (Zone 9b) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26
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Napa County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (201 days to spare)
Start indoors: Jan 13 Transplant: Feb 10 🍅 Harvest: Apr 7 – May 5
Recommended (50%) ✓ Fits season (189 days to spare)
Start indoors: Jan 29 Transplant: Feb 26 🍅 Harvest: Apr 23 – May 21
Safe Start (90%) ✓ Fits season (175 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: May 28 – Jun 25

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 Napa County

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

Soil pH

Your soil pH (6.7–7.5) is within Chinese Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Chinese Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Chinese Cabbage.

How to Plant Chinese 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 Chinese Cabbage

6
successive plantings in your 273-day season

Sow every 5.7 weeks. Last sowing by Sep 17 to harvest before frost.

For a dedicated fall crop, sow by Oct 01.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.5″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 4,136 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Chinese Cabbage

Chinese 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 Chinese Cabbage Needs Rainfall You Supplement Action
Jan 7.5" 0" ❄️ Dormant
Feb 6.5" 7.8" 0" ✅ Rainfall sufficient
Mar 6.5" 5.8" 0.7" 💧 Light watering
Apr 6.5" 2.3" 4.2" 🚿 Regular watering
May 6.5" 0.8" 5.7" 🚿 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" 1.3" 5.2" 🚿 Regular watering
Nov 6.5" 3.3" 3.2" 💧 Light watering
Dec 5.6" 0" ❄️ Dormant

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

Chinese 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.

Chinese Cabbage needs ~960 GDD — county provides 4,384 GDD Excellent fit

Chinese Cabbage Planting Timeline — Napa County, CA

Chinese Cabbage Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors February 26 Feb 26 – Mar 12
Direct Sow February 5 Feb 5 – Feb 26
Harvest April 23 Apr 23 – May 21
Fall Sowing October 1 Oct 1 – Oct 15

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

Month-by-Month Timeline

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

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

273 days in Napa County

Growing Tips for Chinese Cabbage in Napa County

Direct sow Chinese Cabbage outdoors after February 26 in Napa County when soil has warmed and frost danger has passed.

Common pests for Chinese 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 to avoid bolting. Start seeds indoors or direct sow in late summer. Keep soil consistently moist and provide shade in warm weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chinese Cabbage in Napa County, CA?

Napa County is in Zone 9b with an average last frost of February 26. Plan your Chinese Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Napa County, CA?

Napa County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 26.

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Your Napa County Garden Planner — Free

A 24-page printable planner built for Napa 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 Napa County, CA. 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.