Blog

When to Plant Zinnia in Stephens County, TX

Stephens County, Texas Zone 8a June

This month in Stephens County, Texas

June is a pivotal month for Stephens County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 4
Avg. first frost November 10
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.1 hrs
  1. Basket week: zinnia

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

To set up a strong July, finish these tasks
  • First harvests: zinnia

Instant PDF download. No spam, unsubscribe any time.

Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Stephens County, Texas is in USDA Zone 8a. The average last spring frost is April 4 and the first fall frost is November 10, giving you a growing season of approximately 220 days.

At an elevation of 3,055 feet, Stephens County receives approximately 63.4 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Zinnia during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Zinnia root diseases.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Stephens County, TX (Zone 8a) Long season
220 days
Last Spring Frost April 4
220 growing days
First Fall Frost November 10

Stephens County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Zinnia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (23 days to spare)
Start indoors: Feb 21 Transplant: Mar 14 🌸 Bloom: May 23 – Oct 10
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 7 Transplant: Mar 28 🌸 Bloom: Jun 6 – Oct 24
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Mar 19 Transplant: Apr 9 🌸 Bloom: Jun 18 – Nov 5

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 Stephens County

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

Soil pH

Your soil pH (6.7–7.7) overlaps with Zinnia's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Zinnia.

How to Plant Zinnia

0.3"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Zinnia

4
successive plantings in your 220-day season

Sow every 6.9 weeks. Last sowing by Sep 01 to harvest before frost.

Zinnia Water Budget

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

Monthly Watering Guide for Zinnia

Zinnia 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 Zinnia Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 2.2" 7.1" 0" ✅ Rainfall sufficient
May 2.2" 9.8" 0" ✅ Rainfall sufficient
Jun 2.2" 10.6" 0" ✅ Rainfall sufficient
Jul 2.2" 7.2" 0" ✅ Rainfall sufficient
Aug 2.2" 7.3" 0" ✅ Rainfall sufficient
Sep 2.2" 6.5" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 1.6" 0" ❄️ Dormant

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

Zinnia 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.

Zinnia needs ~1,235 GDD — county provides 4,180 GDD Excellent fit

Zinnia Planting Timeline — Stephens County, TX

Zinnia Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors March 28 Mar 28 – Apr 11
Direct Sow March 28 Mar 28 – Apr 18
Bloom June 6 Jun 6 – Oct 24

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

220 days in Stephens County

Growing Tips for Zinnia in Stephens County

Direct sow Zinnia outdoors after April 04 in Stephens County when soil has warmed and frost danger has passed.

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

General growing tips

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zinnia in Stephens County, TX?

Stephens County is in Zone 8a with an average last frost of April 4. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stephens County, TX?

Stephens County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is April 4 and first fall frost is November 10.

🌱

Your Stephens County Garden Planner — Free

A 22-page printable planner built for Stephens County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Stephens 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.