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When to Plant Dahlias in Refugio County, TX

Refugio County, Texas Zone 9b June

What to do in June

Here's what deserves your attention in Refugio County, Texas this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 16
Avg. first frost December 6
Soil temp (4") 87°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Pick dahlias

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to 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.

Refugio County, Texas is in USDA Zone 9b. The average last spring frost is February 16 and the first fall frost is December 6, giving you a growing season of approximately 293 days.

At an elevation of 1,000 feet, Refugio County receives approximately 68.4 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Dahlias may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Dahlias root diseases.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Refugio County, TX (Zone 9b) Year-round
293 days
Last Spring Frost February 16
293 growing days
First Fall Frost December 6

Refugio County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Dahlias Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Transplant: Feb 2 🌸 Bloom: Apr 13 – Oct 26
Recommended (50%) ✓ Fits season (27 days to spare)
Transplant: Feb 16 🌸 Bloom: Apr 27 – Nov 9
Safe Start (90%) ✓ Fits season (19 days to spare)
Transplant: Mar 12 🌸 Bloom: May 21 – Dec 3

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 Refugio County

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

Soil pH

Your soil pH (6.7–7.2) is within Dahlias's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.0%). 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 293-day season

Sow every 8 weeks. Last sowing by Aug 08 to harvest before frost.

Dahlias Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 60 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 2" 0" ❄️ Dormant
Feb 4.3" 2.1" 2.2" 🚿 Regular watering
Mar 4.3" 3.9" 0.4" 💧 Light watering
Apr 4.3" 8.3" 0" ✅ Rainfall sufficient
May 4.3" 9.2" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 9.3" 0" ✅ Rainfall sufficient
Aug 4.3" 8" 0" ✅ Rainfall sufficient
Sep 4.3" 5.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 4.3" 1.8" 2.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Refugio 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 ~2,589 GDD — county provides 8,011 GDD Excellent fit

Dahlias Planting Timeline — Refugio County, TX

Dahlias Planting Calendar

Activity When Date Range
Transplant Outdoors February 16 Feb 16 – Mar 2
Direct Sow February 16 Feb 16 – Mar 9
Bloom April 27 Apr 27 – Nov 9

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 Bloom
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 9b

📆 Growing Season

293 days in Refugio County

Growing Tips for Dahlias in Refugio County

Direct sow Dahlias outdoors after February 16 in Refugio County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in Refugio County, provide afternoon shade for Dahlias and water deeply in the morning.

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 Refugio County, TX?

Refugio County is in Zone 9b with an average last frost of February 16. Plan your Dahlias planting based on this frost date — see the calendar above for exact timing.

What planting zone is Refugio County, TX?

Refugio County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 16 and first fall frost is December 6.

🌱

Your Refugio County Garden Planner — Free

A 22-page printable planner built for Refugio 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.

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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 Refugio 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.