When to Plant Watercress in San Patricio County, TX
May in the garden — San Patricio County, Texas
Your garden in San Patricio County, Texas is working on a schedule, even when you're not. Here's where you should be this May.
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.
San Patricio County, Texas is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 9, giving you a growing season of approximately 300 days.
At an elevation of 2,449 feet, San Patricio County receives approximately 54.7 inches of rainfall annually with predominantly loam soil. Summer highs average 100°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.
San Patricio County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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 San Patricio 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 San Patricio County is excellent for Watercress — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is low (1.9%). Add 2-3 inches of compost before planting Watercress.
How to Plant Watercress
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Watercress
Sow every 4.6 weeks. Last sowing by Oct 10 to harvest before frost.
For a dedicated fall crop, sow by Oct 14.
Plant Water Budget
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" | 1.7" | 4.8" | 🚿 Regular watering |
| Mar | 6.5" | 3.8" | 2.7" | 💧 Light watering |
| Apr | 6.5" | 6.4" | 0.1" | 💧 Light watering |
| May | 6.5" | 8.5" | 0" | ✅ Rainfall sufficient |
| Jun | 6.5" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 6.5" | 7.5" | 0" | ✅ Rainfall sufficient |
| Aug | 6.5" | 5.6" | 0.9" | 💧 Light watering |
| Sep | 6.5" | 5" | 1.5" | 💧 Light watering |
| Oct | 6.5" | 3.1" | 3.4" | 🚿 Regular watering |
| Nov | 6.5" | 2" | 4.5" | 🚿 Regular watering |
| Dec | 6.5" | 1.4" | 5.1" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in San Patricio 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 Planting Timeline — San Patricio County, TX
Watercress Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 15 | Jan 15 – Jan 29 |
| Transplant Outdoors | February 12 | Feb 12 – Feb 26 |
| Direct Sow | January 22 | Jan 22 – Feb 12 |
| Harvest | March 26 | Mar 26 – Apr 30 |
| Fall Sowing | October 14 | Oct 14 – Oct 28 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | Harvest |
| April | Harvest |
| May | — |
| 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
300 days in San Patricio County
Growing Tips for Watercress in San Patricio County
Direct sow Watercress outdoors after February 12 in San Patricio County when soil has warmed and frost danger has passed.
With summer highs reaching 100°F in San Patricio County, provide afternoon shade for Watercress and water deeply in the morning.
Your generous 301.0-day season in San Patricio 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 →
Watercress in Other Locations
Frequently Asked Questions
When should I plant Watercress in San Patricio County, TX?
San Patricio County is in Zone 9b with an average last frost of February 12. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Patricio County, TX?
San Patricio County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 12 and first fall frost is December 9.
Your San Patricio County Garden Planner — Free
A 24-page printable planner built for San Patricio 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.