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When to Plant Petunia in DeWitt County, TX

DeWitt County, Texas Zone 9a June

Your June gardening checklist

Your DeWitt County, Texas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost March 2
Avg. first frost November 26
Soil temp (4") 83°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Collect petunia at their peak

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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

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Petunias (Petunia x hybrida) are warm-season tender annuals prized for their prolific, trumpet-shaped blooms in nearly every color. They perform from hanging baskets to garden borders and bloom continuously from late spring until frost, provided spent flowers are removed regularly.

DeWitt County, Texas is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 26, giving you a growing season of approximately 269 days.

At an elevation of 1,649 feet, DeWitt County receives approximately 62.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Petunia during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Petunia root diseases.

Annual Blooms in Summer Pollinator-friendly Fragrant
DeWitt County, TX (Zone 9a) Long season
269 days
Last Spring Frost March 2
269 growing days
First Fall Frost November 26

DeWitt County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Petunia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Start indoors: Dec 24 Transplant: Feb 4 🌸 Bloom: Apr 15 – Sep 16
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Jan 5 Transplant: Feb 16 🌸 Bloom: Apr 27 – Sep 28
Safe Start (90%) ✓ Fits season (53 days to spare)
Start indoors: Jan 28 Transplant: Mar 11 🌸 Bloom: May 20 – Oct 21

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 DeWitt County

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

Soil pH

Your soil pH (6.8–7.8) is more alkaline than Petunia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Petunia.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Petunia.

How to Plant Petunia

12"
Between Plants
12"
Between Rows

Succession Planting Petunia

4
successive plantings in your 269-day season

Sow every 8 weeks. Last sowing by Aug 28 to harvest before frost.

Petunia Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 949 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Petunia

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

Month Petunia Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 5.9" 0" ✅ Rainfall sufficient
May 4.3" 9.1" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 6.9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.9" 0" ✅ Rainfall sufficient
Sep 4.3" 5.6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

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

Petunia 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.

Petunia needs ~1,460 GDD — county provides 4,909 GDD Excellent fit

Petunia Planting Timeline — DeWitt County, TX

Petunia Planting Calendar

Activity When Date Range
Start Indoors January 5 Jan 5 – Jan 19
Transplant Outdoors February 16 Feb 16 – Mar 2
Bloom April 27 Apr 27 – Sep 28

· 12" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

269 days in DeWitt County

Growing Tips for Petunia in DeWitt County

Direct sow Petunia outdoors after March 02 in DeWitt County when soil has warmed and frost danger has passed.

Common pests for Petunia in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8–10 weeks before last frost; seeds need light to germinate — press onto moist mix surface, do not cover. Transplant after last frost once nights stay above 50°F. Pinch back leggy plants mid-summer to encourage bushy re-bloom. Wave/spreading types tolerate light shade but bloom less. Feed every 2 weeks with balanced fertilizer once established.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Petunia in DeWitt County, TX?

DeWitt County is in Zone 9a with an average last frost of March 2. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.

What planting zone is DeWitt County, TX?

DeWitt County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 26.

🌱

Your DeWitt County Garden Planner — Free

A 22-page printable planner built for DeWitt 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 DeWitt 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.