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When to Plant Watercress in McMullen County, TX

McMullen County, Texas Zone 9b May

Your May gardening checklist

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

Avg. last frost February 20
Avg. first frost December 1
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Collect watercress at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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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.

McMullen County, Texas 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 3,741 feet, McMullen County receives approximately 58 inches of rainfall annually with predominantly loam soil. Summer highs average 103°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.

McMullen County, TX (Zone 9b) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1

McMullen County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (217 days to spare)
Start indoors: Jan 6 Transplant: Feb 3 🍅 Harvest: Mar 17 – Apr 21
Recommended (50%) ✓ Fits season (207 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🍅 Harvest: Apr 3 – May 8
Safe Start (90%) ✓ Fits season (200 days to spare)
Start indoors: Feb 17 Transplant: Mar 17 🍅 Harvest: Apr 28 – Jun 2

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 McMullen County

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

Soil pH

Your soil pH (6.8–7.2) is within Watercress's preferred range (6.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). 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 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
1.5″/week
Rainfall provides
0.9″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,964 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 1.6" 0" ❄️ Dormant
Feb 6.5" 2" 4.5" 🚿 Regular watering
Mar 6.5" 3.7" 2.8" 💧 Light watering
Apr 6.5" 6.4" 0.1" 💧 Light watering
May 6.5" 9.4" 0" ✅ Rainfall sufficient
Jun 6.5" 9.8" 0" ✅ Rainfall sufficient
Jul 6.5" 7.3" 0" ✅ Rainfall sufficient
Aug 6.5" 6.5" 0" ✅ Rainfall sufficient
Sep 6.5" 4.6" 1.9" 💧 Light watering
Oct 6.5" 3.5" 3" 💧 Light watering
Nov 6.5" 1.7" 4.8" 🚿 Regular watering
Dec 6.5" 1.3" 5.2" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in McMullen 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 ~1,362 GDD — county provides 7,766 GDD Excellent fit

Watercress Planting Timeline — McMullen County, TX

Watercress Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors February 20 Feb 20 – Mar 6
Direct Sow January 30 Jan 30 – Feb 20
Harvest April 3 Apr 3 – May 8
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors
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: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

284 days in McMullen County

Growing Tips for Watercress in McMullen County

Direct sow Watercress outdoors after February 20 in McMullen County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in McMullen County, provide afternoon shade for Watercress and water deeply in the morning.

Your generous 285.0-day season in McMullen 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 McMullen County, TX?

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

What planting zone is McMullen County, TX?

McMullen County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.

🌱

Your McMullen County Garden Planner — Free

A 24-page printable planner built for McMullen County (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 McMullen 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.