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When to Plant Nasturtium in Frio County, TX

Frio County, Texas Zone 9a June

Your June gardening checklist

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Bring in the nasturtium

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

To set up a strong July, finish these tasks
  • First harvests: nasturtium

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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.

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 Nasturtium during the growing season. 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
Frio County, TX (Zone 9a) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26

Frio County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Jan 16 Transplant: Jan 23 🌸 Bloom: Mar 20 – Sep 18
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Jan 29 Transplant: Feb 5 🌸 Bloom: Apr 2 – Oct 1
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Feb 21 Transplant: Feb 28 🌸 Bloom: Apr 25 – Oct 24

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 Nasturtium's growing requirements.

Soil pH

Your soil pH (6.4–7.2) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Nasturtium.

Organic Matter

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

How to Plant Nasturtium

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

Succession Planting Nasturtium

5
successive plantings in your 273-day season

Sow every 6.3 weeks. Last sowing by Sep 22 to harvest before frost.

Nasturtium Water Budget

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

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 1.2" 0" ❄️ Dormant
Feb 2.2" 1.9" 0.3" 💧 Light watering
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 4.9" 0" ✅ Rainfall sufficient
May 2.2" 7.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.4" 0" ✅ Rainfall sufficient
Jul 2.2" 6.3" 0" ✅ Rainfall sufficient
Aug 2.2" 5.2" 0" ✅ Rainfall sufficient
Sep 2.2" 4.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 1.6" 0.6" 💧 Light 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.

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 ~1,185 GDD — county provides 5,411 GDD Excellent fit

Nasturtium Planting Timeline — Frio County, TX

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors February 5 Feb 5 – Feb 19
Direct Sow February 5 Feb 5 – Feb 26
Bloom April 2 Apr 2 – Oct 1

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Transplant Outdoors Direct Sow
March
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
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 9a

📆 Growing Season

273 days in Frio County

Growing Tips for Nasturtium in Frio County

Direct sow Nasturtium outdoors after February 26 in Frio 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 Frio County, TX?

Frio County is in Zone 9a with an average last frost of February 26. Plan your Nasturtium 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 22-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.

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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 Frio County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

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