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When to Plant Watercress in Willacy County, TX

Willacy County, Texas Zone 10a May

Willacy County, Texas gardeners: here's your May plan

Welcome to May in Zone 10a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.3 hrs

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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.

Willacy County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Watercress may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

Willacy County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22
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Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (256 days to spare)
Start indoors: Dec 20 Transplant: Jan 17 🍅 Harvest: Feb 28 – Apr 4
Recommended (50%) ✓ Fits season (244 days to spare)
Start indoors: Jan 7 Transplant: Feb 4 🍅 Harvest: Mar 18 – Apr 22
Safe Start (90%) ✓ Fits season (221 days to spare)
Start indoors: Feb 4 Transplant: Mar 4 🍅 Harvest: Apr 15 – May 20

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 Willacy County

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

Soil pH

Your soil pH (6.5–7.3) is within Watercress's preferred range (6.5–7.5).

Soil Texture

The loam soil in Willacy 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 (2.1%). 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

9
successive plantings in your 321-day season

Sow every 4.6 weeks. Last sowing by Oct 23 to harvest before frost.

For a dedicated fall crop, sow by Oct 27.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 3,750 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 6.5" 2.3" 4.2" 🚿 Regular watering
Mar 6.5" 4.4" 2.1" 💧 Light watering
Apr 6.5" 6.4" 0.1" 💧 Light watering
May 6.5" 9.5" 0" ✅ Rainfall sufficient
Jun 6.5" 9.7" 0" ✅ Rainfall sufficient
Jul 6.5" 9" 0" ✅ Rainfall sufficient
Aug 6.5" 8.5" 0" ✅ Rainfall sufficient
Sep 6.5" 6.3" 0.2" 💧 Light watering
Oct 6.5" 3.8" 2.7" 💧 Light watering
Nov 6.5" 2.6" 3.9" 🚿 Regular watering
Dec 6.5" 1.8" 4.7" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Willacy 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 ~1,325 GDD — county provides 8,533 GDD Excellent fit

Watercress Planting Timeline — Willacy County, TX

Watercress Planting Calendar

Activity When Date Range
Start Indoors January 7 Jan 7 – Jan 21
Transplant Outdoors February 4 Feb 4 – Feb 18
Direct Sow January 14 Jan 14 – Feb 4
Harvest March 18 Mar 18 – Apr 22
Fall Sowing October 27 Oct 27 – Nov 10

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
June
July
August
September
October Fall Sowing
November Fall Sowing
December
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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: ideal

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Willacy County

Growing Tips for Watercress in Willacy County

Direct sow Watercress outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Willacy County, provide afternoon shade for Watercress and water deeply in the morning.

Your generous 322.0-day season in Willacy 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 Willacy County, TX?

Willacy County is in Zone 10a with an average last frost of February 4. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

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Your Willacy County Garden Planner — Free

A 24-page printable planner built for Willacy County (Zone 10a). 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 Willacy 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.