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When to Plant Nasturtium in Oldham County, TX

Oldham County, Texas Zone 7a June

Your June gardening checklist

Welcome to June in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 19
Avg. first frost October 18
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 14.4 hrs
  1. Basket week: nasturtium

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Looking ahead to July
  • 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.

Oldham County, Texas is in USDA Zone 7a. The average last spring frost is April 19 and the first fall frost is October 18, giving you a growing season of approximately 182 days.

At an elevation of 2,350 feet, Oldham County receives approximately 56 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Nasturtium during the growing season. Sandy soil warms quickly in spring — great for early planting — but Nasturtium will need more frequent watering and organic matter to retain nutrients. 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
Oldham County, TX (Zone 7a) Moderate season
182 days
Last Spring Frost April 19
182 growing days
First Fall Frost October 18
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Oldham County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🌸 Bloom: Jun 9 – Oct 13
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🌸 Bloom: Jun 14 – Oct 18
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Apr 5 Transplant: May 3 🌸 Bloom: Jun 28 – Nov 1

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 Oldham County

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

Soil pH

Your soil pH (7.2–8.3) overlaps with Nasturtium's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Nasturtium.

How to Plant Nasturtium

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

Succession Planting Nasturtium

3
successive plantings in your 182-day season

Sow every 6.3 weeks. Last sowing by Aug 14 to harvest before frost.

Nasturtium Water Budget

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

Water stress score is 8/10 — 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 3.4" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 2.2" 1.8" 0.4" 💧 Light watering
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 1.9" 0.3" 💧 Light watering
Jul 2.2" 10.4" 0" ✅ Rainfall sufficient
Aug 2.2" 12.7" 0" ✅ Rainfall sufficient
Sep 2.2" 6.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.7" 0" ✅ Rainfall sufficient
Nov 3.1" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Oldham 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 ~1,230 GDD — county provides 3,731 GDD Excellent fit

Nasturtium Planting Timeline — Oldham County, TX

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 19 Apr 19 – May 10
Bloom June 14 Jun 14 – Oct 18

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

182 days in Oldham County

Growing Tips for Nasturtium in Oldham County

Direct sow Nasturtium outdoors after April 19 in Oldham County when soil has warmed and frost danger has passed.

Sandy soil in Oldham County dries quickly — mulch Nasturtium with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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 Oldham County, TX?

Oldham County is in Zone 7a with an average last frost of April 19. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oldham County, TX?

Oldham County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 19 and first fall frost is October 18.

🌱

Your Oldham County Garden Planner — Free

A 22-page printable planner built for Oldham County (Zone 7a). 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 Oldham 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.