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When to Plant Portulaca in Austin County, TX

Austin County, Texas Zone 9a June

Top priorities for Austin County, Texas gardeners in June

Welcome to June in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 28
Avg. first frost November 29
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for portulaca

    If you can't use it all right away, check the food-preservation section of your planner.

Looking ahead to July
  • First harvests: portulaca

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Portulaca (Portulaca grandiflora), commonly called moss rose, is a succulent- stemmed annual built for hot, dry, low-fertility conditions where other flowers fail. Its silky, rose-like blooms open in full sun and close at night or on cloudy days. Excellent for slopes, rock gardens, containers, and parking-strip plantings where irrigation is limited. One of the easiest annuals for neglect- proof summer color.

Austin County, Texas is in USDA Zone 9a. The average last spring frost is February 28 and the first fall frost is November 29, giving you a growing season of approximately 274 days.

At an elevation of 350 feet, Austin County receives approximately 68.9 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Portulaca during the growing season. Clay soil retains moisture well for Portulaca, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Portulaca root diseases.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Austin County, TX (Zone 9a) Year-round
274 days
Last Spring Frost February 28
274 growing days
First Fall Frost November 29

Austin County Soil Profile

Soil Type

Clay

Soil pH

6.8-8.1

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Jan 16 Transplant: Jan 30 🌸 Bloom: Mar 20 – Sep 25
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Jan 31 Transplant: Feb 14 🌸 Bloom: Apr 4 – Oct 10
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Feb 22 Transplant: Mar 8 🌸 Bloom: Apr 26 – Nov 1

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 Austin County

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

Soil pH

Your soil pH (6.8–8.1) is more alkaline than Portulaca prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (41% clay) in Austin County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Portulaca.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Succession Planting Portulaca

6
successive plantings in your 274-day season

Sow every 5.7 weeks. Last sowing by Sep 20 to harvest before frost.

Portulaca Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 Portulaca

Portulaca 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 Portulaca Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 2.2" 2.4" 0" ✅ Rainfall sufficient
Mar 2.2" 4.3" 0" ✅ Rainfall sufficient
Apr 2.2" 7.2" 0" ✅ Rainfall sufficient
May 2.2" 9.6" 0" ✅ Rainfall sufficient
Jun 2.2" 11.9" 0" ✅ Rainfall sufficient
Jul 2.2" 8.5" 0" ✅ Rainfall sufficient
Aug 2.2" 9.2" 0" ✅ Rainfall sufficient
Sep 2.2" 5.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.6" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 1.8" 0" ❄️ Dormant

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

Portulaca 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.

Portulaca needs ~1,050 GDD — county provides 4,812 GDD Excellent fit

Portulaca Planting Timeline — Austin County, TX

Portulaca Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors February 14 Feb 14 – Feb 28
Direct Sow February 14 Feb 14 – Mar 7
Bloom April 4 Apr 4 – Oct 10

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Transplant Outdoors Direct Sow
March Direct Sow
April Bloom
May Bloom
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

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

274 days in Austin County

Growing Tips for Portulaca in Austin County

Direct sow Portulaca outdoors after February 28 in Austin County when soil has warmed and frost danger has passed.

With Austin County's clay soil (41% clay), work in 3-4 inches of compost before planting Portulaca. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Direct-sow after last frost once soil warms to 65°F, or start indoors 4–6 weeks before last frost. Seed is tiny — surface sow and do not cover. Thin to proper spacing after germination. Thrives in poor, well-drained soil; rich or wet soil produces lush foliage but fewer blooms. No deadheading required — plants are self-cleaning. Double-flowered varieties hold blooms open longer in overcast conditions.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Portulaca in Austin County, TX?

Austin County is in Zone 9a with an average last frost of February 28. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Austin County, TX?

Austin County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 28 and first fall frost is November 29.

🌱

Your Austin County Garden Planner — Free

A 22-page printable planner built for Austin 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 Austin 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.