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When to Plant Watercress in Kerr County, TX

Kerr County, Texas Zone 8b May

May to-do list for Kerr County, Texas

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

Avg. last frost March 24
Avg. first frost November 11
Soil temp (4") 62°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Bring in the watercress

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

June will be here before you know it — start on
  • First harvests: 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.

Kerr County, Texas is in USDA Zone 8b. The average last spring frost is March 24 and the first fall frost is November 11, giving you a growing season of approximately 232 days.

At an elevation of 3,907 feet, Kerr County receives approximately 52 inches of rainfall annually with predominantly loam soil. Summer highs average 93°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.

Kerr County, TX (Zone 8b) Long season
232 days
Last Spring Frost March 24
232 growing days
First Fall Frost November 11

Kerr County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (156 days to spare)
Start indoors: Feb 5 Transplant: Mar 12 🍅 Harvest: Apr 23 – May 28
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: May 5 – Jun 9
Safe Start (90%) ✓ Fits season (149 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: May 28 – Jul 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 Kerr County

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

Soil pH

Your soil pH (6.4–7.6) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Watercress

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Watercress

7
successive plantings in your 232-day season

Sow every 4.6 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Sep 02.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,153 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 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 6.5" 3.4" 3.1" 💧 Light watering
Apr 6.5" 5.7" 0.8" 💧 Light watering
May 6.5" 6.7" 0" ✅ Rainfall sufficient
Jun 6.5" 9.2" 0" ✅ Rainfall sufficient
Jul 6.5" 7.3" 0" ✅ Rainfall sufficient
Aug 6.5" 6.1" 0.4" 💧 Light watering
Sep 6.5" 4.8" 1.7" 💧 Light watering
Oct 6.5" 3.1" 3.4" 🚿 Regular watering
Nov 6.5" 1.7" 4.8" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Kerr 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 ~988 GDD — county provides 4,582 GDD Excellent fit

Watercress Planting Timeline — Kerr County, TX

Watercress Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors March 24 Mar 24 – Apr 7
Direct Sow March 10 Mar 10 – Mar 31
Harvest May 5 May 5 – Jun 9
Fall Sowing September 2 Sep 2 – Sep 16

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

232 days in Kerr County

Growing Tips for Watercress in Kerr County

Direct sow Watercress outdoors after March 24 in Kerr County when soil has warmed and frost danger has passed.

Your generous 232.0-day season in Kerr 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 Kerr County, TX?

Kerr County is in Zone 8b with an average last frost of March 24. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kerr County, TX?

Kerr County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 24 and first fall frost is November 11.

🌱

Your Kerr County Garden Planner — Free

A 24-page printable planner built for Kerr County (Zone 8b). 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 Kerr 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.