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When to Plant Portulaca in Johnson County, NE

Johnson County, Nebraska Zone 5b July

July in Johnson County, Nebraska — your action list

A quick July briefing for Johnson County, Nebraska gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 24
Avg. first frost October 7
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. Basket week: portulaca

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to August
  • 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.

Johnson County, Nebraska is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 7, giving you a growing season of approximately 166 days.

At an elevation of 658 feet, Johnson County receives approximately 21.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Portulaca during the growing season.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Johnson County, NE (Zone 5b) Moderate season
166 days
Last Spring Frost April 24
166 growing days
First Fall Frost October 7

Johnson County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.5

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🌸 Bloom: Jun 16 – Sep 22
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Mar 20 Transplant: May 1 🌸 Bloom: Jun 19 – Sep 25
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Apr 6 Transplant: May 18 🌸 Bloom: Jul 6 – Oct 12

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 Johnson County

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

Soil pH

Your soil pH (6.3–7.5) overlaps with Portulaca's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Portulaca.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Portulaca.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Succession Planting Portulaca

3
successive plantings in your 166-day season

Sow every 5.7 weeks. Last sowing by Jul 29 to harvest before frost.

Portulaca Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 197 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 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.2" 1.9" 0.3" 💧 Light watering
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 3.3" 0" ✅ Rainfall sufficient
Jul 2.2" 3" 0" ✅ Rainfall sufficient
Aug 2.2" 2.6" 0" ✅ Rainfall sufficient
Sep 2.2" 2.2" 0" ✅ Rainfall sufficient
Oct 2.2" 1.5" 0.7" 💧 Light watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Johnson 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 ~870 GDD — county provides 2,407 GDD Excellent fit

Portulaca Planting Timeline — Johnson County, NE

Portulaca Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 1 May 1 – May 15
Direct Sow May 1 May 1 – May 22
Bloom June 19 Jun 19 – Sep 25

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors 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 · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

166 days in Johnson County

Growing Tips for Portulaca in Johnson County

Direct sow Portulaca outdoors after April 24 in Johnson County when soil has warmed and frost danger has passed.

Johnson County receives only 21" 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 Johnson County, NE?

Johnson County is in Zone 5b with an average last frost of April 24. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, NE?

Johnson County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 7.

🌱

Your Johnson County Garden Planner — Free

A 22-page printable planner built for Johnson County (Zone 5b). 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 Johnson County, NE. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.