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When to Plant Portulaca in Millard County, UT

Millard County, Utah Zone 6a June

Millard County, Utah gardeners: here's your June plan

A quick June briefing for Millard County, Utah gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 16
Avg. first frost September 30
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 14.7 hrs
  1. Get portulaca seeds going inside

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

Coming up in July — start thinking about
  • 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.

Millard County, Utah is in USDA Zone 6a. The average last spring frost is May 16 and the first fall frost is September 30, giving you a growing season of approximately 137 days.

At an elevation of 6,525 feet, Millard County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Portulaca to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Millard County, UT (Zone 6a) Short season
137 days
Last Spring Frost May 16
137 growing days
First Fall Frost September 30

Millard County Soil Profile

Soil Type

Loam

Soil pH

6.5-8

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: May 14 🌸 Bloom: Jul 2 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Apr 11 Transplant: May 23 🌸 Bloom: Jul 11 – Oct 24
Safe Start (90%) ✗ May not fit
Start indoors: May 5 Transplant: Jun 16 🌸 Bloom: Aug 4 – Nov 17

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 Millard County

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

Soil pH

Your soil pH (6.5–8.0) is more alkaline than Portulaca prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Portulaca.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Succession Planting Portulaca

3
successive plantings in your 137-day season

Sow every 5.7 weeks. Last sowing by Jul 22 to harvest before frost.

Portulaca Water Budget

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

Water stress score is 8/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 2.2" 2.7" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Millard 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 ~780 GDD — county provides 1,781 GDD Excellent fit

Portulaca Planting Timeline — Millard County, UT

Portulaca Planting Calendar

Activity When Date Range
Start Indoors April 11 Apr 11 – Apr 25
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 23 May 23 – Jun 13
Bloom July 11 Jul 11 – Oct 24

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
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 6a

📆 Growing Season

137 days in Millard County

Growing Tips for Portulaca in Millard County

Direct sow Portulaca outdoors after May 16 in Millard County when soil has warmed and frost danger has passed.

Millard County receives only 24" of rain annually. Portulaca needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Millard County, UT?

Millard County is in Zone 6a with an average last frost of May 16. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Millard County, UT?

Millard County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 16 and first fall frost is September 30.

🌱

Your Millard County Garden Planner — Free

A 22-page printable planner built for Millard County (Zone 6a). 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 Millard County, UT. 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.