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When to Plant Napa Cabbage in St. John the Baptist Parish, LA

St. John the Baptist Parish, Louisiana Zone 9b May

May in the garden — St. John the Baptist Parish, Louisiana

Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 20
Avg. first frost December 1
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Bring in the napa cabbage

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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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.

St. John the Baptist Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.

At an elevation of 309 feet, St. John the Baptist Parish receives approximately 53.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Napa Cabbage may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Napa Cabbage will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Napa Cabbage root diseases.

St. John the Baptist Parish, LA (Zone 9b) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1

St. John the Baptist Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (197 days to spare)
Start indoors: Jan 9 Transplant: Feb 6 🍅 Harvest: Apr 3 – May 8
Recommended (50%) ✓ Fits season (193 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🍅 Harvest: Apr 17 – May 22
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 St. John the Baptist Parish

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

Soil pH

Your soil pH (4.8–6.1) is more acidic than Napa Cabbage prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. John the Baptist Parish warms quickly in spring but drains fast. Napa Cabbage will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Napa Cabbage.

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 284-day season

Sow every 6.3 weeks. Last sowing by Sep 17 to harvest before frost.

For a dedicated fall crop, sow by Oct 06.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 787 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 4" 0" ❄️ Dormant
Feb 6.5" 4" 2.5" 💧 Light watering
Mar 6.5" 4.6" 1.9" 💧 Light watering
Apr 6.5" 4" 2.5" 💧 Light watering
May 6.5" 4.7" 1.8" 💧 Light watering
Jun 6.5" 5" 1.5" 💧 Light watering
Jul 6.5" 6.3" 0.2" 💧 Light watering
Aug 6.5" 4.7" 1.8" 💧 Light watering
Sep 6.5" 4.3" 2.2" 💧 Light watering
Oct 6.5" 3.7" 2.8" 💧 Light watering
Nov 6.5" 3.5" 3" 💧 Light watering
Dec 6.5" 4.8" 1.7" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in St. John the Baptist Parish). 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 ~1,771 GDD — county provides 7,766 GDD Excellent fit

Napa Cabbage Planting Timeline — St. John the Baptist Parish, LA

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors February 20 Feb 20 – Mar 6
Direct Sow January 30 Jan 30 – Feb 20
Harvest April 17 Apr 17 – May 22
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors
April Harvest
May Harvest
June
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_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

284 days in St. John the Baptist Parish

Growing Tips for Napa Cabbage in St. John the Baptist Parish

Direct sow Napa Cabbage outdoors after February 20 in St. John the Baptist Parish when soil has warmed and frost danger has passed.

Sandy soil in St. John the Baptist Parish dries quickly — mulch Napa Cabbage with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 103°F in St. John the Baptist Parish, 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 St. John the Baptist Parish, LA?

St. John the Baptist Parish is in Zone 9b with an average last frost of February 20. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. John the Baptist Parish, LA?

St. John the Baptist Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.

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Your St. John the Baptist Parish Garden Planner — Free

A 24-page printable planner built for St. John the Baptist Parish (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 St. John the Baptist Parish, LA. 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.