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When to Plant Dahlias in Dimmit County, TX

Dimmit County, Texas Zone 9a June

Your June gardening checklist

We've pulled the most time-sensitive tasks for Dimmit County, Texas this June and put them front and centre. Tackle them in order.

Avg. last frost February 26
Avg. first frost December 1
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Collect dahlias at their peak

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

A few tasks this June that'll pay off in July
  • First harvests: dahlias

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Dahlias (Dahlia spp.) are the undisputed stars of the late-summer and fall garden, producing an extraordinary range of flower forms — from compact pompons to dinner plate-sized blooms spanning 12 inches — in virtually every color except true blue. Blooming from midsummer until the first hard frost, a single tuber grows into a massive, flower-laden plant that can produce dozens of cut flowers per week. Modern breeding has expanded the palette and forms dramatically; the American Dahlia Society recognizes over 20 flower forms. Extremely rewarding for gardeners willing to invest in the planting, staking, and (in cold zones) annual lifting of tubers.

Dimmit County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is December 1, giving you a growing season of approximately 278 days.

At an elevation of 2,638 feet, Dimmit County receives approximately 63.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Dahlias during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Dahlias root diseases.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Dimmit County, TX (Zone 9a) Year-round
278 days
Last Spring Frost February 26
278 growing days
First Fall Frost December 1

Dimmit County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Dahlias Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Transplant: Feb 13 🌸 Bloom: Apr 24 – Oct 23
Recommended (50%) ✓ Fits season (26 days to spare)
Transplant: Feb 26 🌸 Bloom: May 7 – Nov 5
Safe Start (90%) ✓ Fits season (20 days to spare)
Transplant: Mar 22 🌸 Bloom: May 31 – Nov 29

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 Dimmit County

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

Soil pH

Your soil pH (6.5–7.3) is within Dahlias's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Dahlias.

How to Plant Dahlias

5"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Dahlias

4
successive plantings in your 278-day season

Sow every 8 weeks. Last sowing by Aug 03 to harvest before frost.

Dahlias Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 121 gal / 100 sq ft

Monthly Watering Guide for Dahlias

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

Month Dahlias Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 4.3" 2" 2.3" 🚿 Regular watering
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 6.3" 0" ✅ Rainfall sufficient
May 4.3" 9.1" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 8.6" 0" ✅ Rainfall sufficient
Aug 4.3" 8.1" 0" ✅ Rainfall sufficient
Sep 4.3" 5.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 4.3" 1.4" 2.9" 🚿 Regular watering

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

Dahlias 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.

Dahlias needs ~1,948 GDD — county provides 5,719 GDD Excellent fit

Dahlias Planting Timeline — Dimmit County, TX

Dahlias Planting Calendar

Activity When Date Range
Transplant Outdoors February 26 Feb 26 – Mar 12
Direct Sow February 26 Feb 26 – Mar 19
Bloom May 7 May 7 – Nov 5

Plant 5" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

278 days in Dimmit County

Growing Tips for Dahlias in Dimmit County

Direct sow Dahlias outdoors after February 26 in Dimmit County when soil has warmed and frost danger has passed.

Common pests for Dahlias in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant tubers after all danger of frost has passed and soil temperature reaches 60°F — typically 1–2 weeks after last frost in most zones. Lay tubers horizontally 4–6 inches deep with the eye (growth point) facing up. Do not water until sprouts emerge; wet soil rots dormant tubers. Stake tall varieties (over 3 feet) at planting time to avoid root disturbance later. Pinch growing tips at 12–16 inches to encourage branching and more blooms. Deadhead regularly to extend the blooming season. In zones 8b and warmer, tubers can overwinter in the ground with a layer of mulch. In zones 3–8a, lift tubers after the first killing frost, cure for a week, and store in slightly damp vermiculite or peat at 40–50°F until spring. Divide tubers every year or two; each division must have an eye (bud) to grow.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dahlias in Dimmit County, TX?

Dimmit County is in Zone 9a with an average last frost of February 26. Plan your Dahlias planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dimmit County, TX?

Dimmit County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is December 1.

🌱

Your Dimmit County Garden Planner — Free

A 22-page printable planner built for Dimmit 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 Dimmit 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.