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When to Plant Tarragon in St. Helena Parish, LA

St. Helena Parish, Louisiana Zone 8b April

St. Helena Parish, Louisiana gardeners: here's your April plan

Welcome to April in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 5
Avg. first frost November 30
Soil temp (4") 61°F
Watering Moderate
Pest pressure High
Daylight 12.8 hrs
Before May arrives, get these ready
  • First harvests: tarragon

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French tarragon is a perennial herb with slender leaves and a distinctive anise-like flavor essential in French cooking. It does not produce viable seed and must be propagated vegetatively.

St. Helena Parish, Louisiana is in USDA Zone 8b. 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 Tarragon may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Tarragon will need more frequent watering and organic matter to retain nutrients.

St. Helena Parish, LA (Zone 8b) 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 (138 days to spare)
Transplant: Feb 22 🍅 Harvest: Apr 26 – Jul 5
Recommended (50%) ✓ Fits season (130 days to spare)
Transplant: Mar 12 🍅 Harvest: May 14 – Jul 23
Safe Start (90%) ✓ Fits season (124 days to spare)
Transplant: Apr 2 🍅 Harvest: Jun 4 – Aug 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. Helena Parish

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

Soil pH

Your soil pH (4.8–6.5) is more acidic than Tarragon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Helena Parish warms quickly in spring but drains fast. Tarragon 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 Tarragon.

How to Plant Tarragon

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

Succession Planting Tarragon

5
successive plantings in your 270-day season

Sow every 6.9 weeks. Last sowing by Sep 01 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Tarragon

Tarragon needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.

Month Tarragon Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 1.7" 5.5" 0" ✅ Rainfall sufficient
Apr 1.7" 3.3" 0" ✅ Rainfall sufficient
May 1.7" 3.6" 0" ✅ Rainfall sufficient
Jun 1.7" 4.9" 0" ✅ Rainfall sufficient
Jul 1.7" 4.7" 0" ✅ Rainfall sufficient
Aug 1.7" 5.1" 0" ✅ Rainfall sufficient
Sep 1.7" 3.6" 0" ✅ Rainfall sufficient
Oct 1.7" 3.3" 0" ✅ Rainfall sufficient
Nov 1.7" 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.

Tarragon 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.

Tarragon needs ~1,650 GDD — county provides 5,940 GDD Excellent fit

Tarragon Planting Timeline — St. Helena Parish, LA

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors March 12 Mar 12 – Mar 26
Harvest May 14 May 14 – Jul 23

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.4"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

270 days in St. Helena Parish

Growing Tips for Tarragon in St. Helena Parish

Direct sow Tarragon 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 Tarragon 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. Helena Parish, provide afternoon shade for Tarragon and water deeply in the morning.

Common pests for Tarragon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Purchase plants or divisions as French tarragon does not grow true from seed. Plant in well-drained soil. Divide every 3-4 years to maintain vigor. Harvest tips regularly for best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

St. Helena Parish is in Zone 8b with an average last frost of March 5. Plan your Tarragon 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 8b. The average last spring frost is March 5 and first fall frost is November 30.

🌱

Your St. Helena Parish Garden Planner — Free

A 24-page printable planner built for St. Helena Parish (Zone 8b). 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: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.