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When to Plant Kohlrabi in St. Mary Parish, LA

St. Mary Parish, Louisiana Zone 9b May

May in St. Mary Parish, Louisiana — your action list

May is a pivotal month for St. Mary Parish, Louisiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 14
Avg. first frost December 5
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Basket week: kohlrabi

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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Kohlrabi is an unusual brassica that forms a swollen stem above ground with a mild, sweet turnip-like flavor. Both the bulb and tender leaves are edible.

St. Mary Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 5, giving you a growing season of approximately 294 days.

At an elevation of 252 feet, St. Mary Parish receives approximately 48.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Kohlrabi may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Kohlrabi will need more frequent watering and organic matter to retain nutrients.

St. Mary Parish, LA (Zone 9b) Year-round
294 days
Last Spring Frost February 14
294 growing days
First Fall Frost December 5

St. Mary Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (211 days to spare)
Start indoors: Jan 8 Transplant: Feb 5 🍅 Harvest: Mar 26 – Apr 30
Recommended (50%) ✓ Fits season (210 days to spare)
Start indoors: Jan 17 Transplant: Feb 14 🍅 Harvest: Apr 4 – May 9
Safe Start (90%) ✓ Fits season (200 days to spare)
Start indoors: Feb 11 Transplant: Mar 11 🍅 Harvest: Apr 29 – Jun 3

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. Mary Parish

How your county's soil matches Kohlrabi's growing requirements.

Soil pH

Your soil pH (4.8–6.4) is more acidic than Kohlrabi prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Mary Parish warms quickly in spring but drains fast. Kohlrabi will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Kohlrabi.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Kohlrabi.

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

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

Succession Planting Kohlrabi

7
successive plantings in your 294-day season

Sow every 5.1 weeks. Last sowing by Oct 01 to harvest before frost.

For a dedicated fall crop, sow by Oct 10.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Kohlrabi

Kohlrabi needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Kohlrabi Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3" 3.4" 0" ✅ Rainfall sufficient
Mar 3" 5.1" 0" ✅ Rainfall sufficient
Apr 3" 3.8" 0" ✅ Rainfall sufficient
May 3" 3.8" 0" ✅ Rainfall sufficient
Jun 3" 3.6" 0" ✅ Rainfall sufficient
Jul 3" 5.6" 0" ✅ Rainfall sufficient
Aug 3" 5.1" 0" ✅ Rainfall sufficient
Sep 3" 3.5" 0" ✅ Rainfall sufficient
Oct 3" 3.1" 0" ✅ Rainfall sufficient
Nov 3" 3.9" 0" ✅ Rainfall sufficient
Dec 3" 4.2" 0" ✅ Rainfall sufficient

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

Kohlrabi 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.

Kohlrabi needs ~1,169 GDD — county provides 6,268 GDD Excellent fit

Kohlrabi Planting Timeline — St. Mary Parish, LA

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors February 14 Feb 14 – Feb 28
Direct Sow January 24 Jan 24 – Feb 14
Harvest April 4 Apr 4 – May 9
Fall Sowing October 10 Oct 10 – Oct 24

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

294 days in St. Mary Parish

Growing Tips for Kohlrabi in St. Mary Parish

Direct sow Kohlrabi outdoors after February 14 in St. Mary Parish when soil has warmed and frost danger has passed.

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

Your generous 295.0-day season in St. Mary Parish allows multiple plantings of Kohlrabi. Sow every 22.0 days for continuous harvest.

Common pests for Kohlrabi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest when bulbs are 2-3 inches in diameter for best texture and flavor. Larger bulbs may become woody and fibrous.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in St. Mary Parish, LA?

St. Mary Parish is in Zone 9b with an average last frost of February 14. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary Parish, LA?

St. Mary Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 5.

🌱

Your St. Mary Parish Garden Planner — Free

A 24-page printable planner built for St. Mary 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. Mary 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.