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When to Plant Watercress in La Salle County, TX

La Salle County, Texas Zone 9a May

May in La Salle County, Texas — your action list

Each item below is timed to La Salle County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 14
Avg. first frost December 3
Soil temp (4") 67°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Basket week: watercress

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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.

La Salle County, Texas is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 3, giving you a growing season of approximately 292 days.

At an elevation of 2,270 feet, La Salle County receives approximately 57.2 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Watercress during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

La Salle County, TX (Zone 9a) Year-round
292 days
Last Spring Frost February 14
292 growing days
First Fall Frost December 3

La Salle County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (223 days to spare)
Start indoors: Jan 2 Transplant: Jan 30 🍅 Harvest: Mar 13 – Apr 17
Recommended (50%) ✓ Fits season (215 days to spare)
Start indoors: Jan 17 Transplant: Feb 14 🍅 Harvest: Mar 28 – May 2
Safe Start (90%) ✓ Fits season (204 days to spare)
Start indoors: Feb 14 Transplant: Mar 14 🍅 Harvest: Apr 25 – May 30

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 La Salle County

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

Soil pH

Your soil pH (6.5–7.6) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

The loam soil in La Salle County is excellent for Watercress — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Watercress is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help 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 292-day season

Sow every 4.6 weeks. Last sowing by Oct 04 to harvest before frost.

For a dedicated fall crop, sow by Oct 08.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,947 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 1.5" 0" ❄️ Dormant
Feb 6.5" 2" 4.5" 🚿 Regular watering
Mar 6.5" 3.4" 3.1" 💧 Light watering
Apr 6.5" 5.5" 1" 💧 Light watering
May 6.5" 7.4" 0" ✅ Rainfall sufficient
Jun 6.5" 10.2" 0" ✅ Rainfall sufficient
Jul 6.5" 7.3" 0" ✅ Rainfall sufficient
Aug 6.5" 7" 0" ✅ Rainfall sufficient
Sep 6.5" 5.8" 0.7" 💧 Light watering
Oct 6.5" 3.6" 2.9" 💧 Light watering
Nov 6.5" 2" 4.5" 🚿 Regular watering
Dec 6.5" 1.6" 4.9" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in La Salle County). 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 ~950 GDD — county provides 5,567 GDD Excellent fit

Watercress Planting Timeline — La Salle County, TX

Watercress Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors February 14 Feb 14 – Feb 28
Direct Sow January 24 Jan 24 – Feb 14
Harvest March 28 Mar 28 – May 2
Fall Sowing October 8 Oct 8 – Oct 22

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

292 days in La Salle County

Growing Tips for Watercress in La Salle County

Direct sow Watercress outdoors after February 14 in La Salle County when soil has warmed and frost danger has passed.

Your generous 293.0-day season in La Salle County 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 La Salle County, TX?

La Salle County is in Zone 9a with an average last frost of February 14. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is La Salle County, TX?

La Salle County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 3.

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A 24-page printable planner built for La Salle County (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 La Salle County, TX. 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.