When to Plant Watercress in Frio County, TX
Your May planting checklist for Frio County, Texas
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Frio County, Texas.
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Start harvesting watercress
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
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.
Frio County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 3,892 feet, Frio County receives approximately 51 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.
Frio County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.2
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 Frio County
How your county's soil matches Watercress's growing requirements.
Soil pH
Your soil pH (6.4–7.2) overlaps with Watercress's range (6.5–7.5), though not a perfect match.
Soil Texture
The loam soil in Frio 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 (2.2%). Annual compost additions will help 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 Sep 27 to harvest before frost.
For a dedicated fall crop, sow by Oct 01.
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Mar | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Apr | 6.5" | 4.9" | 1.6" | 💧 Light watering |
| May | 6.5" | 7.5" | 0" | ✅ Rainfall sufficient |
| Jun | 6.5" | 9.4" | 0" | ✅ Rainfall sufficient |
| Jul | 6.5" | 6.3" | 0.2" | 💧 Light watering |
| Aug | 6.5" | 5.2" | 1.3" | 💧 Light watering |
| Sep | 6.5" | 4.6" | 1.9" | 💧 Light watering |
| Oct | 6.5" | 3.4" | 3.1" | 💧 Light watering |
| Nov | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Frio 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 — Frio County, TX
Watercress Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 29 | Jan 29 – Feb 12 |
| Transplant Outdoors | February 26 | Feb 26 – Mar 12 |
| Direct Sow | February 5 | Feb 5 – Feb 26 |
| Harvest | April 9 | Apr 9 – May 14 |
| Fall Sowing | October 1 | Oct 1 – Oct 15 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| 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: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
273 days in Frio County
Growing Tips for Watercress in Frio County
Direct sow Watercress outdoors after February 26 in Frio County when soil has warmed and frost danger has passed.
Your generous 274.0-day season in Frio 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 Frio County, TX?
Frio County is in Zone 9a with an average last frost of February 26. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.
What planting zone is Frio County, TX?
Frio County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 26.
Your Frio County Garden Planner — Free
A 24-page printable planner built for Frio 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.