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When to Plant Basil in St. Landry Parish, LA

St. Landry Parish, Louisiana Zone 9a May

St. Landry Parish, Louisiana gardeners: here's your May plan

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 19
Avg. first frost December 1
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Start harvesting basil

    If you can't use it all right away, check the food-preservation section of your planner.

Before June arrives, get these ready
  • First harvests: basil

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

St. Landry Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 19 and the first fall frost is December 1, giving you a growing season of approximately 285 days.

At an elevation of 370 feet, St. Landry Parish receives approximately 59.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Basil may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Basil will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Basil root diseases.

St. Landry Parish, LA (Zone 9a) Year-round
285 days
Last Spring Frost February 19
285 growing days
First Fall Frost December 1
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St. Landry Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (160 days to spare)
Start indoors: Dec 27 Transplant: Feb 14 🍅 Harvest: Apr 11 – Jun 13
Recommended (50%) ✓ Fits season (159 days to spare)
Start indoors: Jan 8 Transplant: Feb 26 🍅 Harvest: Apr 23 – Jun 25
Safe Start (90%) ✓ Fits season (153 days to spare)
Start indoors: Jan 28 Transplant: Mar 18 🍅 Harvest: May 13 – Jul 15

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. Landry Parish

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

Soil pH

Your soil pH (4.8–6.0) is more acidic than Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Basil.

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

6
successive plantings in your 285-day season

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

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 4.4" 0" ❄️ Dormant
Feb 2.6" 4.7" 0" ✅ Rainfall sufficient
Mar 2.6" 6" 0" ✅ Rainfall sufficient
Apr 2.6" 4.1" 0" ✅ Rainfall sufficient
May 2.6" 4.6" 0" ✅ Rainfall sufficient
Jun 2.6" 4.7" 0" ✅ Rainfall sufficient
Jul 2.6" 7" 0" ✅ Rainfall sufficient
Aug 2.6" 6.4" 0" ✅ Rainfall sufficient
Sep 2.6" 4.1" 0" ✅ Rainfall sufficient
Oct 2.6" 4.3" 0" ✅ Rainfall sufficient
Nov 2.6" 4" 0" ✅ Rainfall sufficient
Dec 2.6" 5.6" 0" ✅ Rainfall sufficient

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

Basil 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.

Basil needs ~1,422 GDD — county provides 6,506 GDD Excellent fit

Basil Planting Timeline — St. Landry Parish, LA

Basil Planting Calendar

Activity When Date Range
Start Indoors January 8 Jan 8 – Jan 22
Transplant Outdoors February 26 Feb 26 – Mar 12
Direct Sow February 26 Feb 26 – Mar 19
Harvest April 23 Apr 23 – Jun 25

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

285 days in St. Landry Parish

Growing Tips for Basil in St. Landry Parish

Direct sow Basil outdoors after February 19 in St. Landry Parish when soil has warmed and frost danger has passed.

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

With summer highs reaching 97°F in St. Landry Parish, provide afternoon shade for Basil and water deeply in the morning.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Recommended Basil Varieties for St. Landry Parish

Downy mildew-resistant basil for your humid climate

Prospera (DM-resistant) Amazel Eleonora

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in St. Landry Parish, LA?

St. Landry Parish is in Zone 9a with an average last frost of February 19. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Landry Parish, LA?

St. Landry Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 19 and first fall frost is December 1.

🌱

Your St. Landry Parish Garden Planner — Free

A 24-page printable planner built for St. Landry Parish (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 St. Landry 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.