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When to Plant Portulaca in Cache County, UT

Cache County, Utah Zone 6a June

This month in Cache County, Utah

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 11
Avg. first frost September 2
Soil temp (4") 52°F
Watering Critical
Pest pressure High
Daylight 15 hrs
  1. Move portulaca from tray to bed

    Frost risk is low now in Cache County, Utah. If you've been covering beds overnight, you can stop.

  2. Seed portulaca outdoors

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Before July arrives, get these ready
  • Starting indoors: 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.

Cache County, Utah is in USDA Zone 6a. The average last spring frost is June 11 and the first fall frost is September 2, giving you a growing season of approximately 83 days.

At an elevation of 6,265 feet, Cache County receives approximately 15.5 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. With low rainfall, drip irrigation is essential for growing Portulaca successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Cache County, UT (Zone 6a) Very short season
83 days
Last Spring Frost June 11
83 growing days
First Fall Frost September 2
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Cache County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 10 Transplant: May 22 🌸 Bloom: Jul 10 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: May 7 Transplant: Jun 18 🌸 Bloom: Aug 6 – Nov 19
Safe Start (90%) ✗ May not fit
Start indoors: May 20 Transplant: Jul 1 🌸 Bloom: Aug 19 – Dec 2

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 Cache County

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

Soil pH

Your soil pH (6.6–8.4) is more alkaline than Portulaca prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Cache 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

Portulaca Water Budget

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

Water stress score is 10/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 2.2" 1.1" 1.1" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Cache 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 1,079 GDD Excellent fit

Portulaca Planting Timeline — Cache County, UT

Portulaca Planting Calendar

Activity When Date Range
Start Indoors May 7 May 7 – May 21
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 18 Jun 18 – Jul 9
Bloom August 6 Aug 6 – Nov 19

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

83 days in Cache County

Growing Tips for Portulaca in Cache County

Direct sow Portulaca outdoors after June 11 in Cache County when soil has warmed and frost danger has passed.

Cache County receives only 16" 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 Cache County, UT?

Cache County is in Zone 6a with an average last frost of June 11. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cache County, UT?

Cache County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is June 11 and first fall frost is September 2.

🌱

Your Cache County Garden Planner — Free

A 22-page printable planner built for Cache 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.

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 Cache 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.