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When to Plant Snapdragon in Dallam County, TX

Dallam County, Texas Zone 6b July

July to-do list for Dallam County, Texas

A quick July briefing for Dallam County, Texas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 26
Avg. first frost October 14
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Time to start snapdragon inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Pick snapdragon

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

Coming up in August — start thinking about
  • First harvests: snapdragon

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Snapdragons (Antirrhinum majus) are classic cool-season annuals whose upright spikes of dragon-lipped flowers are among spring's most dramatic displays. Tolerating light frosts, they bloom from early spring until summer heat shuts them down — then often revive in fall. In zones 9-11 they are grown as fall-planted winter annuals and may re-seed to naturalize.

Dallam County, Texas is in USDA Zone 6b. The average last spring frost is April 26 and the first fall frost is October 14, giving you a growing season of approximately 171 days.

At an elevation of 3,388 feet, Dallam County receives approximately 54.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Snapdragon may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Snapdragon will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Snapdragon root diseases.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Dallam County, TX (Zone 6b) Moderate season
171 days
Last Spring Frost April 26
171 growing days
First Fall Frost October 14

Dallam County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.9-8.4

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Feb 9 Transplant: Apr 20 🌸 Bloom: Jun 29 – Sep 14
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Feb 15 Transplant: Apr 26 🌸 Bloom: Jul 5 – Sep 20
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Feb 27 Transplant: May 8 🌸 Bloom: Jul 17 – Oct 2

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 Dallam County

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

Soil pH

Your soil pH (7.9–8.4) is more alkaline than Snapdragon prefers (6.2–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.1%). Add 2-3 inches of compost before planting Snapdragon.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Succession Planting Snapdragon

2
successive plantings in your 171-day season

Sow every 8 weeks. Last sowing by Jul 06 to harvest before frost.

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/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 Snapdragon

Snapdragon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Snapdragon Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 1" 3.3" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 9.9" 0" ✅ Rainfall sufficient
Aug 4.3" 11.7" 0" ✅ Rainfall sufficient
Sep 4.3" 8" 0" ✅ Rainfall sufficient
Oct 4.3" 4" 0.3" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

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

Snapdragon 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.

Snapdragon needs ~1,870 GDD — county provides 3,762 GDD Excellent fit

Snapdragon Planting Timeline — Dallam County, TX

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 5 Apr 5 – Apr 26
Bloom July 5 Jul 5 – Sep 20

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6.2–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

171 days in Dallam County

Growing Tips for Snapdragon in Dallam County

Direct sow Snapdragon outdoors after April 26 in Dallam County when soil has warmed and frost danger has passed.

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

With summer highs reaching 96°F in Dallam County, provide afternoon shade for Snapdragon and water deeply in the morning.

General growing tips

Start indoors 10-12 weeks before last frost; seeds need light to germinate — press into moist medium and do not cover. Transplant after hardening off, even if light frosts remain. Pinch seedlings once to encourage branching. Deadhead to prolong blooming. In zones 8-11, sow in fall for a winter-to-spring show. Tall varieties (24-36") make excellent cut flowers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Snapdragon in Dallam County, TX?

Dallam County is in Zone 6b with an average last frost of April 26. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dallam County, TX?

Dallam County, Texas is in USDA Hardiness Zone 6b. The average last spring frost is April 26 and first fall frost is October 14.

🌱

Your Dallam County Garden Planner — Free

A 22-page printable planner built for Dallam County (Zone 6b). 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 Dallam 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.