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When to Plant Watercress in Vermilion Parish, LA

Vermilion Parish, Louisiana Zone 9a May

May to-do list for Vermilion Parish, Louisiana

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

Avg. last frost February 13
Avg. first frost December 5
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. It's harvest week for watercress

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

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Watercress is a semi-aquatic plant with a peppery, tangy flavor rich in vitamins and minerals. It grows naturally along streams and can be cultivated in containers with standing water.

Vermilion 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 430 feet, Vermilion Parish receives approximately 54.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°F, so Watercress may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Watercress will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

Vermilion Parish, LA (Zone 9a) Year-round
295 days
Last Spring Frost February 13
295 growing days
First Fall Frost December 5
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Vermilion Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (222 days to spare)
Start indoors: Jan 3 Transplant: Jan 31 🍅 Harvest: Mar 14 – Apr 18
Recommended (50%) ✓ Fits season (218 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: Mar 27 – May 1
Safe Start (90%) ✓ Fits season (208 days to spare)
Start indoors: Feb 9 Transplant: Mar 9 🍅 Harvest: Apr 20 – May 25

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 Vermilion Parish

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

Soil pH

Your soil pH (5.0–6.3) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Watercress.

Organic Matter

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

How to Plant Watercress

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 Watercress

8
successive plantings in your 295-day season

Sow every 4.6 weeks. Last sowing by Oct 06 to harvest before frost.

For a dedicated fall crop, sow by Oct 10.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 744 gal / 100 sq ft

Monthly Watering Guide for Watercress

Watercress needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watercress Needs Rainfall You Supplement Action
Jan 4.7" 0" ❄️ Dormant
Feb 6.5" 4.2" 2.3" 💧 Light watering
Mar 6.5" 5.8" 0.7" 💧 Light watering
Apr 6.5" 4.8" 1.7" 💧 Light watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 4.5" 2" 💧 Light watering
Jul 6.5" 4.9" 1.6" 💧 Light watering
Aug 6.5" 4.5" 2" 💧 Light watering
Sep 6.5" 4.5" 2" 💧 Light watering
Oct 6.5" 3" 3.5" 🚿 Regular watering
Nov 6.5" 3.9" 2.6" 💧 Light watering
Dec 6.5" 5" 1.5" 💧 Light watering

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

Watercress 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.

Watercress needs ~1,212 GDD — county provides 7,178 GDD Excellent fit

Watercress Planting Timeline — Vermilion Parish, LA

Watercress Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow January 23 Jan 23 – Feb 13
Harvest March 27 Mar 27 – May 1
Fall Sowing October 10 Oct 10 – Oct 24

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February 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

1.5"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

295 days in Vermilion Parish

Growing Tips for Watercress in Vermilion Parish

Direct sow Watercress outdoors after February 13 in Vermilion Parish when soil has warmed and frost danger has passed.

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

With summer highs reaching 99°F in Vermilion Parish, provide afternoon shade for Watercress and water deeply in the morning.

Your generous 296.0-day season in Vermilion Parish allows multiple plantings of Watercress. Sow every 20.0 days for continuous harvest.

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

General growing tips

Grow in containers with trays of water kept fresh. Provide partial shade and cool conditions. Harvest stems by cutting above water level. Replace water frequently to prevent stagnation.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watercress in Vermilion Parish, LA?

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

What planting zone is Vermilion Parish, LA?

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

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Your Vermilion Parish Garden Planner — Free

A 24-page printable planner built for Vermilion 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 Vermilion 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.