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When to Plant Napa Cabbage in Washington County, TX

Washington County, Texas Zone 9a May

May in Washington County, Texas — your action list

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Avg. last frost March 2
Avg. first frost November 27
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest napa cabbage as they ripen

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

Get ahead of June
  • 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.

Washington County, Texas is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.

At an elevation of 386 feet, Washington County receives approximately 58.9 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Napa Cabbage during the growing season. Clay soil retains moisture well for Napa Cabbage, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Napa Cabbage root diseases.

Washington County, TX (Zone 9a) Year-round
270 days
Last Spring Frost March 2
270 growing days
First Fall Frost November 27

Washington County Soil Profile

Soil Type

Clay

Soil pH

6.9-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (182 days to spare)
Start indoors: Jan 18 Transplant: Feb 15 🍅 Harvest: Apr 12 – May 17
Recommended (50%) ✓ Fits season (179 days to spare)
Start indoors: Feb 2 Transplant: Mar 2 🍅 Harvest: Apr 27 – Jun 1
Safe Start (90%) ✓ Fits season (180 days to spare)
Start indoors: Feb 22 Transplant: Mar 22 🍅 Harvest: May 17 – Jun 21

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 Washington County

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

Soil pH

Your soil pH (6.9–8.4) is more alkaline than Napa Cabbage prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Your clay soil in Washington County is workable for Napa Cabbage. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (2.6%). 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

5
successive plantings in your 270-day season

Sow every 6.3 weeks. Last sowing by Sep 13 to harvest before frost.

For a dedicated fall crop, sow by Oct 02.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,403 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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 6.5" 4.3" 2.2" 💧 Light watering
Apr 6.5" 5.8" 0.7" 💧 Light watering
May 6.5" 8.3" 0" ✅ Rainfall sufficient
Jun 6.5" 9.9" 0" ✅ Rainfall sufficient
Jul 6.5" 7" 0" ✅ Rainfall sufficient
Aug 6.5" 7.4" 0" ✅ Rainfall sufficient
Sep 6.5" 5.2" 1.3" 💧 Light watering
Oct 6.5" 4.2" 2.3" 💧 Light watering
Nov 6.5" 2" 4.5" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington 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 ~1,138 GDD — county provides 4,725 GDD Excellent fit

Napa Cabbage Planting Timeline — Washington County, TX

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 – Feb 16
Transplant Outdoors March 2 Mar 2 – Mar 16
Direct Sow February 9 Feb 9 – Mar 2
Harvest April 27 Apr 27 – Jun 1
Fall Sowing October 2 Oct 2 – Oct 16

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

270 days in Washington County

Growing Tips for Napa Cabbage in Washington County

Direct sow Napa Cabbage outdoors after March 02 in Washington County when soil has warmed and frost danger has passed.

With Washington County's clay soil (37% clay), work in 3-4 inches of compost before planting Napa Cabbage. Avoid tilling when soil is wet to prevent compaction.

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 Washington County, TX?

Washington County is in Zone 9a with an average last frost of March 2. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, TX?

Washington County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 27.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 9a). 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 Washington County, TX. 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.