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When to Plant Basil in St. Martin Parish, LA

St. Martin Parish, Louisiana Zone 9a May

Your May planting checklist for St. Martin Parish, Louisiana

Here's what deserves your attention in St. Martin Parish, Louisiana this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 13
Avg. first frost December 5
Soil temp (4") 75°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs
  1. Basket week: basil

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

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. Martin Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 5, giving you a growing season of approximately 295 days.

At an elevation of 417 feet, St. Martin Parish receives approximately 55.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°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. Martin Parish, LA (Zone 9a) Year-round
295 days
Last Spring Frost February 13
295 growing days
First Fall Frost December 5

St. Martin Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5.2-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (173 days to spare)
Start indoors: Dec 20 Transplant: Feb 7 🍅 Harvest: Apr 4 – Jun 6
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 17 – Jun 19
Safe Start (90%) ✓ Fits season (159 days to spare)
Start indoors: Jan 26 Transplant: Mar 16 🍅 Harvest: May 11 – Jul 13

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. Martin Parish

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

Soil pH

Your soil pH (5.2–6.0) is more acidic than Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Basil.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Basil.

How to Plant Basil

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

Succession Planting Basil

7
successive plantings in your 295-day season

Sow every 5.7 weeks. Last sowing by Sep 21 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/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 5.1" 0" ❄️ Dormant
Feb 2.6" 4.4" 0" ✅ Rainfall sufficient
Mar 2.6" 5.7" 0" ✅ Rainfall sufficient
Apr 2.6" 3.8" 0" ✅ Rainfall sufficient
May 2.6" 3.7" 0" ✅ Rainfall sufficient
Jun 2.6" 5.1" 0" ✅ Rainfall sufficient
Jul 2.6" 6.4" 0" ✅ Rainfall sufficient
Aug 2.6" 5.6" 0" ✅ Rainfall sufficient
Sep 2.6" 3.8" 0" ✅ Rainfall sufficient
Oct 2.6" 3.3" 0" ✅ Rainfall sufficient
Nov 2.6" 4.4" 0" ✅ Rainfall sufficient
Dec 2.6" 4.1" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in St. Martin 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 ~1,375 GDD — county provides 6,512 GDD Excellent fit

Basil Planting Timeline — St. Martin Parish, LA

Basil Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 – Jan 16
Transplant Outdoors February 20 Feb 20 – Mar 6
Direct Sow February 20 Feb 20 – Mar 13
Harvest April 17 Apr 17 – Jun 19

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

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

295 days in St. Martin Parish

Growing Tips for Basil in St. Martin Parish

Direct sow Basil outdoors after February 13 in St. Martin Parish when soil has warmed and frost danger has passed.

Sandy soil in St. Martin 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 96°F in St. Martin 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. Martin 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. Martin Parish, LA?

St. Martin Parish is in Zone 9a with an average last frost of February 13. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Martin Parish, LA?

St. Martin Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 5.

🌱

Your St. Martin Parish Garden Planner — Free

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