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When to Plant Watercress in Jasper County, TX

Jasper County, Texas Zone 9a May

May in Jasper County, Texas — your action list

Here's what deserves your attention in Jasper County, Texas this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost March 3
Avg. first frost November 22
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Start harvesting watercress

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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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.

Jasper County, Texas is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 22, giving you a growing season of approximately 264 days.

At an elevation of 97 feet, Jasper County receives approximately 71.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°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.

Jasper County, TX (Zone 9a) Long season
264 days
Last Spring Frost March 3
264 growing days
First Fall Frost November 22
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Jasper County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (193 days to spare)
Start indoors: Jan 20 Transplant: Feb 17 🍅 Harvest: Mar 31 – May 5
Recommended (50%) ✓ Fits season (187 days to spare)
Start indoors: Feb 3 Transplant: Mar 3 🍅 Harvest: Apr 14 – May 19
Safe Start (90%) ✓ Fits season (182 days to spare)
Start indoors: Feb 28 Transplant: Mar 28 🍅 Harvest: May 9 – Jun 13

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 Jasper County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

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 264-day season

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

For a dedicated fall crop, sow by Sep 27.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.1″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 841 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 1.6" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 6.5" 4.2" 2.3" 💧 Light watering
Apr 6.5" 7.3" 0" ✅ Rainfall sufficient
May 6.5" 10.8" 0" ✅ Rainfall sufficient
Jun 6.5" 12.7" 0" ✅ Rainfall sufficient
Jul 6.5" 7.8" 0" ✅ Rainfall sufficient
Aug 6.5" 8.4" 0" ✅ Rainfall sufficient
Sep 6.5" 7.2" 0" ✅ Rainfall sufficient
Oct 6.5" 4.9" 1.6" 💧 Light watering
Nov 6.5" 2.3" 4.2" 🚿 Regular watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jasper 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 ~1,138 GDD — county provides 6,006 GDD Excellent fit

Watercress Planting Timeline — Jasper County, TX

Watercress Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 – Feb 17
Transplant Outdoors March 3 Mar 3 – Mar 17
Direct Sow February 10 Feb 10 – Mar 3
Harvest April 14 Apr 14 – May 19
Fall Sowing September 27 Sep 27 – Oct 11

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9a

📆 Growing Season

264 days in Jasper County

Growing Tips for Watercress in Jasper County

Direct sow Watercress outdoors after March 03 in Jasper County when soil has warmed and frost danger has passed.

Sandy soil in Jasper County 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 97°F in Jasper County, provide afternoon shade for Watercress and water deeply in the morning.

Your generous 264.0-day season in Jasper 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 Jasper County, TX?

Jasper County is in Zone 9a with an average last frost of March 3. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jasper County, TX?

Jasper County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 22.

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Your Jasper County Garden Planner — Free

A 24-page printable planner built for Jasper 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 Jasper 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.