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When to Plant Arugula in St. Helena Parish, LA

St. Helena Parish, Louisiana Zone 9a May

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

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

Avg. last frost March 5
Avg. first frost November 30
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Collect arugula at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

A few tasks this May that'll pay off in June
  • First harvests: arugula

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Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.

St. Helena Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 30, giving you a growing season of approximately 270 days.

At an elevation of 437 feet, St. Helena Parish receives approximately 50 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Arugula may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Arugula will need more frequent watering and organic matter to retain nutrients.

St. Helena Parish, LA (Zone 9a) Year-round
270 days
Last Spring Frost March 5
270 growing days
First Fall Frost November 30
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St. Helena Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (180 days to spare)
Start indoors: Jan 18 Transplant: Feb 15 🍅 Harvest: Mar 22 – May 24
Recommended (50%) ✓ Fits season (172 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: Apr 9 – Jun 11
Safe Start (90%) ✓ Fits season (166 days to spare)
Start indoors: Feb 26 Transplant: Mar 26 🍅 Harvest: Apr 30 – Jul 2

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. Helena Parish

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

Soil pH

Your soil pH (4.8–6.5) is more acidic than Arugula prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.7%). Add 2-3 inches of compost before planting Arugula.

How to Plant Arugula

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Arugula

11
successive plantings in your 270-day season

Sow every 3.4 weeks. Last sowing by Oct 11 to harvest before frost.

For a dedicated fall crop, sow by Oct 05.

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 Arugula

Arugula 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 Arugula Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 2.6" 5.5" 0" ✅ Rainfall sufficient
Apr 2.6" 3.3" 0" ✅ Rainfall sufficient
May 2.6" 3.6" 0" ✅ Rainfall sufficient
Jun 2.6" 4.9" 0" ✅ Rainfall sufficient
Jul 2.6" 4.7" 0" ✅ Rainfall sufficient
Aug 2.6" 5.1" 0" ✅ Rainfall sufficient
Sep 2.6" 3.6" 0" ✅ Rainfall sufficient
Oct 2.6" 3.3" 0" ✅ Rainfall sufficient
Nov 2.6" 4.4" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

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

Arugula 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.

Arugula needs ~880 GDD — county provides 5,940 GDD Excellent fit

Arugula Planting Timeline — St. Helena Parish, LA

Arugula Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 12 Feb 12 – Mar 5
Harvest April 9 Apr 9 – Jun 11
Fall Sowing October 5 Oct 5 – Oct 19

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

270 days in St. Helena Parish

Growing Tips for Arugula in St. Helena Parish

Direct sow Arugula outdoors after March 05 in St. Helena Parish when soil has warmed and frost danger has passed.

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

Summer highs in St. Helena Parish reach 96°F — grow Arugula as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 270.0-day season in St. Helena Parish allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.

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

General growing tips

Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Arugula in St. Helena Parish, LA?

St. Helena Parish is in Zone 9a with an average last frost of March 5. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Helena Parish, LA?

St. Helena Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 30.

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Your St. Helena Parish Garden Planner — Free

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