Blog

When to Plant Nasturtium in Webb County, TX

Webb County, Texas Zone 9b July

Your July planting checklist for Webb County, Texas

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

Avg. last frost February 9
Avg. first frost December 9
Soil temp (4") 85°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Harvest nasturtium as they ripen

    If you can't use it all right away, check the food-preservation section of your planner.

Before August arrives, get these ready
  • First harvests: nasturtium

Instant PDF download. No spam, unsubscribe any time.

Nasturtium (Tropaeolum majus) is a fast-growing annual with distinctive round, lily-pad leaves and bold trumpet-shaped blooms in warm oranges, reds, and yellows. Both the flowers and leaves are edible with a peppery watercress flavor. Planted near vegetables, nasturtiums act as a sacrifice trap-crop, luring aphids away from more valuable plants. They thrive in poor, dry soil — rich conditions produce lush foliage but few flowers.

Webb County, Texas is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 9, giving you a growing season of approximately 303 days.

At an elevation of 3,543 feet, Webb County receives approximately 50.9 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Nasturtium may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Nasturtium root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Webb County, TX (Zone 9b) Year-round
303 days
Last Spring Frost February 9
303 growing days
First Fall Frost December 9

Webb County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Dec 22 Transplant: Dec 22 🌸 Bloom: Feb 16 – Aug 31
Recommended (50%) ✓ Fits season (79 days to spare)
Start indoors: Jan 12 Transplant: Jan 12 🌸 Bloom: Mar 9 – Sep 21
Safe Start (90%) ✓ Fits season (67 days to spare)
Start indoors: Feb 5 Transplant: Feb 5 🌸 Bloom: Apr 2 – Oct 15

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 Webb County

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

Soil pH

Your soil pH (6.6–7.7) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Nasturtium.

How to Plant Nasturtium

0.5"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Nasturtium

6
successive plantings in your 303-day season

Sow every 6.3 weeks. Last sowing by Oct 05 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Nasturtium

Nasturtium needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Nasturtium Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 2.2" 1.9" 0.3" 💧 Light watering
Mar 2.2" 2.8" 0" ✅ Rainfall sufficient
Apr 2.2" 5" 0" ✅ Rainfall sufficient
May 2.2" 8.3" 0" ✅ Rainfall sufficient
Jun 2.2" 7.6" 0" ✅ Rainfall sufficient
Jul 2.2" 5.9" 0" ✅ Rainfall sufficient
Aug 2.2" 6.4" 0" ✅ Rainfall sufficient
Sep 2.2" 5.2" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 1.7" 0.5" 💧 Light watering
Dec 2.2" 1.5" 0.7" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Webb County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Nasturtium 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.

Nasturtium needs ~1,275 GDD — county provides 6,460 GDD Excellent fit

Nasturtium Planting Timeline — Webb County, TX

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors January 12 Jan 12 – Jan 26
Direct Sow January 12 Jan 12 – Feb 2
Bloom March 9 Mar 9 – Sep 21

Plant 0.5" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

55–65 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

303 days in Webb County

Growing Tips for Nasturtium in Webb County

Direct sow Nasturtium outdoors after February 09 in Webb County when soil has warmed and frost danger has passed.

General growing tips

Direct-sow large seeds 1/2 inch deep after last frost; soak seeds overnight to speed germination (7-10 days). Nasturtiums dislike root disturbance so direct sowing is strongly preferred. Avoid fertilizing — poor soil brings the best bloom. Trailing types can cover banks and climb trellises; dwarf types suit containers. In hot climates (zones 9+) plant in fall for winter/spring bloom as plants struggle in peak summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Nasturtium in Webb County, TX?

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

What planting zone is Webb County, TX?

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

🌱

Your Webb County Garden Planner — Free

A 22-page printable planner built for Webb 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Webb County, TX. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.