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When to Plant Napa Cabbage in Starr County, TX

Starr County, Texas Zone 9b May

Your May planting checklist for Starr County, Texas

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Starr County, Texas.

Avg. last frost February 3
Avg. first frost December 16
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.3 hrs
  1. Harvest napa cabbage as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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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.

Starr County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 16, giving you a growing season of approximately 316 days.

At an elevation of 2,451 feet, Starr County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Napa Cabbage may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Napa Cabbage root diseases.

Starr County, TX (Zone 9b) Year-round
316 days
Last Spring Frost February 3
316 growing days
First Fall Frost December 16

Starr County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (235 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Mar 15 – Apr 19
Recommended (50%) ✓ Fits season (225 days to spare)
Start indoors: Jan 6 Transplant: Feb 3 🍅 Harvest: Mar 31 – May 5
Safe Start (90%) ✓ Fits season (206 days to spare)
Start indoors: Feb 3 Transplant: Mar 3 🍅 Harvest: Apr 28 – Jun 2

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 Starr County

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

Soil pH

Your soil pH (6.8–7.5) is within Napa Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). 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

6
successive plantings in your 316-day season

Sow every 6.3 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Oct 21.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,593 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 1.6" 0" ❄️ Dormant
Feb 6.5" 1.9" 4.6" 🚿 Regular watering
Mar 6.5" 3.4" 3.1" 💧 Light watering
Apr 6.5" 6.6" 0" ✅ Rainfall sufficient
May 6.5" 8.8" 0" ✅ Rainfall sufficient
Jun 6.5" 7.6" 0" ✅ Rainfall sufficient
Jul 6.5" 7" 0" ✅ Rainfall sufficient
Aug 6.5" 6.4" 0.1" 💧 Light watering
Sep 6.5" 4.9" 1.6" 💧 Light watering
Oct 6.5" 4" 2.5" 💧 Light watering
Nov 6.5" 1.6" 4.9" 🚿 Regular watering
Dec 6.5" 1.6" 4.9" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Starr 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 ~1,528 GDD — county provides 7,449 GDD Excellent fit

Napa Cabbage Planting Timeline — Starr County, TX

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors January 6 Jan 6 – Jan 20
Transplant Outdoors February 3 Feb 3 – Feb 17
Direct Sow January 13 Jan 13 – Feb 3
Harvest March 31 Mar 31 – May 5
Fall Sowing October 21 Oct 21 – Nov 4

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

Month-by-Month Timeline

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

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

316 days in Starr County

Growing Tips for Napa Cabbage in Starr County

Direct sow Napa Cabbage outdoors after February 03 in Starr County when soil has warmed and frost danger has passed.

With summer highs reaching 98°F in Starr County, provide afternoon shade for Napa Cabbage and water deeply in the morning.

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 Starr County, TX?

Starr County is in Zone 9b with an average last frost of February 3. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Starr County, TX?

Starr County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 16.

🌱

Your Starr County Garden Planner — Free

A 24-page printable planner built for Starr 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 Starr 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.