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When to Plant Basil in Washington Parish, LA

Washington Parish, Louisiana Zone 9a May

Your May game plan for Washington Parish, Louisiana

Your garden in Washington Parish, Louisiana is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 11
Avg. first frost November 22
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Collect basil at their peak

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

June prep starts now
  • 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.

Washington Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 11 and the first fall frost is November 22, giving you a growing season of approximately 256 days.

At an elevation of 439 feet, Washington Parish receives approximately 56.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 93°F, providing good warmth for Basil during the growing season. 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.

Washington Parish, LA (Zone 9a) Long season
256 days
Last Spring Frost March 11
256 growing days
First Fall Frost November 22
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Washington Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5.1-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Jan 19 Transplant: Mar 9 🍅 Harvest: May 4 – Jul 6
Recommended (50%) ✓ Fits season (130 days to spare)
Start indoors: Jan 28 Transplant: Mar 18 🍅 Harvest: May 13 – Jul 15
Safe Start (90%) ✓ Fits season (131 days to spare)
Start indoors: Feb 16 Transplant: Apr 6 🍅 Harvest: Jun 1 – Aug 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 Washington Parish

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

Soil pH

Your soil pH (5.1–6.3) is more acidic than Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Washington 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 low (1.9%). Add 2-3 inches of compost before planting Basil.

How to Plant Basil

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

Succession Planting Basil

6
successive plantings in your 256-day season

Sow every 5.7 weeks. Last sowing by Sep 08 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 4.9" 0" ❄️ Dormant
Feb 5" 0" ❄️ Dormant
Mar 2.6" 5.7" 0" ✅ Rainfall sufficient
Apr 2.6" 4.2" 0" ✅ Rainfall sufficient
May 2.6" 4.7" 0" ✅ Rainfall sufficient
Jun 2.6" 4.6" 0" ✅ Rainfall sufficient
Jul 2.6" 5.4" 0" ✅ Rainfall sufficient
Aug 2.6" 5.2" 0" ✅ Rainfall sufficient
Sep 2.6" 3.8" 0" ✅ Rainfall sufficient
Oct 2.6" 4.1" 0" ✅ Rainfall sufficient
Nov 2.6" 4.1" 0" ✅ Rainfall sufficient
Dec 4.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington 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 ~1,234 GDD — county provides 5,056 GDD Excellent fit

Basil Planting Timeline — Washington Parish, LA

Basil Planting Calendar

Activity When Date Range
Start Indoors January 28 Jan 28 – Feb 11
Transplant Outdoors March 18 Mar 18 – Apr 1
Direct Sow March 18 Mar 18 – Apr 8
Harvest May 13 May 13 – Jul 15

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

Month-by-Month Timeline

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

256 days in Washington Parish

Growing Tips for Basil in Washington Parish

Direct sow Basil outdoors after March 11 in Washington Parish when soil has warmed and frost danger has passed.

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

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 Washington 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 Washington Parish, LA?

Washington Parish is in Zone 9a with an average last frost of March 11. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington Parish, LA?

Washington Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 11 and first fall frost is November 22.

🌱

Your Washington Parish Garden Planner — Free

A 24-page printable planner built for Washington 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 Washington 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.