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When to Plant Cilantro in St. Charles Parish, LA

St. Charles Parish, Louisiana Zone 9b May

This month in St. Charles Parish, Louisiana

May is a pivotal month for St. Charles Parish, Louisiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 20
Avg. first frost December 1
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Collect cilantro at their peak

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

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

St. Charles Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.

At an elevation of 154 feet, St. Charles Parish receives approximately 54.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Cilantro may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cilantro will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cilantro root diseases.

St. Charles Parish, LA (Zone 9b) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1
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St. Charles Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (190 days to spare)
Start indoors: Jan 9 Transplant: Jan 30 🍅 Harvest: Mar 13 – May 15
Recommended (50%) ✓ Fits season (186 days to spare)
Start indoors: Jan 23 Transplant: Feb 13 🍅 Harvest: Mar 27 – May 29
Safe Start (90%) ✓ Fits season (173 days to spare)
Start indoors: Feb 22 Transplant: Mar 15 🍅 Harvest: Apr 26 – Jun 28

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. Charles Parish

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

Soil pH

Your soil pH (4.9–6.3) is more acidic than Cilantro prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Cilantro.

Organic Matter

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

How to Plant Cilantro

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

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

Succession Planting Cilantro

8
successive plantings in your 284-day season

Sow every 4.6 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Oct 06.

Plant Water Budget

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

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 2.2" 4.8" 0" ✅ Rainfall sufficient
Mar 2.2" 4.9" 0" ✅ Rainfall sufficient
Apr 2.2" 4.2" 0" ✅ Rainfall sufficient
May 2.2" 4.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 5.9" 0" ✅ Rainfall sufficient
Aug 2.2" 5" 0" ✅ Rainfall sufficient
Sep 2.2" 4.5" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.2" 4.3" 0" ✅ Rainfall sufficient
Dec 2.2" 4" 0" ✅ Rainfall sufficient

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

Cilantro 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.

Cilantro needs ~1,362 GDD — county provides 7,766 GDD Excellent fit

Cilantro Planting Timeline — St. Charles Parish, LA

Cilantro Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow January 30 Jan 30 – Feb 20
Harvest March 27 Mar 27 – May 29
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

284 days in St. Charles Parish

Growing Tips for Cilantro in St. Charles Parish

Direct sow Cilantro outdoors after February 20 in St. Charles Parish when soil has warmed and frost danger has passed.

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

Summer highs in St. Charles Parish reach 103°F — grow Cilantro as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 285.0-day season in St. Charles Parish allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in St. Charles Parish, LA?

St. Charles Parish is in Zone 9b with an average last frost of February 20. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Charles Parish, LA?

St. Charles Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.

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Your St. Charles Parish Garden Planner — Free

A 24-page printable planner built for St. Charles Parish (Zone 9b). 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. Charles 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.