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When to plant Portulaca in Olean, MO

Spring Portulaca in Olean goes in April 13–May 4, once nighttime temps stop dipping near freezing.

When to Plant Portulaca in Olean, MO

Miller County, Missouri Zone 6b August

Top priorities for Miller County, Missouri gardeners in August

Your garden in Miller County, Missouri is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost April 6
Avg. first frost October 27
Soil temp (4") 82°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs
  1. It's harvest week for portulaca

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

September will be here before you know it — start on
  • 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.

Olean, Missouri is in USDA Zone 6b. The average last spring frost is April 6 and the first fall frost is October 27, giving you a growing season of approximately 204 days.

At an elevation of 1,086 feet, Miller County receives approximately 30.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Portulaca during the growing season.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Olean, MO (Zone 6b) Long season
204 days
Last Spring Frost April 6
204 growing days
First Fall Frost October 27

Olean Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🌸 Bloom: May 26 – Sep 15
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Mar 2 Transplant: Apr 13 🌸 Bloom: Jun 1 – Sep 21
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🌸 Bloom: Jun 16 – Oct 6

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 Olean

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

Soil pH

Your soil pH (5.7–6.7) is within Portulaca's preferred range (5.5–7.0).

Soil Texture

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

Drainage

Portulaca prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Portulaca.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Succession Planting Portulaca

4
successive plantings in your 204-day season

Sow every 5.7 weeks. Last sowing by Aug 18 to harvest before frost.

Portulaca Water Budget

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

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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.4" 0" ✅ Rainfall sufficient
Nov 1.8" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Miller 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 ~1,005 GDD — county provides 3,417 GDD Excellent fit

Portulaca Planting Timeline — Olean, MO

Portulaca Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 13 Apr 13 – May 4
Bloom June 1 Jun 1 – Sep 21

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6b

📆 Growing Season

204 days in Miller County

Growing Tips for Portulaca in Olean

Direct sow Portulaca outdoors after April 06 in Miller County when soil has warmed and frost danger has passed.

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 →

When should I plant Portulaca in Olean, MO?

In Olean, MO, plant Portulaca after the last frost (around April 6) and before the first frost (around October 27). Best results when soil holds above 50°F.

What growing zone is Olean, MO for Portulaca?

Olean sits in USDA Zone 6b. Portulaca grows reliably in zones 3a through 11b, so it's a good fit here.

Can Portulaca grow in Olean's climate?

Yes — Portulaca grows well in Olean's temperate climate. Olean averages a 204-day frost-free season, with last frost around April 6 and first frost around October 27.

🌱

Your Miller County Garden Planner — Free

A 22-page printable planner built for Miller County (Zone 6b). 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 Miller County, MO. Local conditions may vary. Last updated: August 2026.