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When to plant Portulaca in Winnebago County County,

Plant Portulaca in Winnebago County County from May 12 to June 2 in spring. Winnebago County County sits in USDA Zone 5a, with last frost around April 28 and first frost on October 6.

When to Plant Portulaca in Winnebago County, IA

Winnebago County, Iowa Zone 5a June

Your June gardening checklist

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Winnebago County, Iowa.

Avg. last frost April 28
Avg. first frost October 6
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
  1. Begin indoor sowing: portulaca

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Pick portulaca

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

To set up a strong July, finish these tasks
  • 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.

Winnebago County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.

At an elevation of 520 feet, Winnebago County receives approximately 32.3 inches of rainfall annually with predominantly silt 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
Winnebago County, IA (Zone 5a) Moderate season
161 days
Last Spring Frost April 28
161 growing days
First Fall Frost October 6
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Winnebago County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Mar 18 Transplant: May 6 🌸 Bloom: Jun 24 – Sep 23
Recommended (50%) ✓ Fits season (7 days to spare)
Start indoors: Mar 24 Transplant: May 12 🌸 Bloom: Jun 30 – Sep 29
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Apr 5 Transplant: May 24 🌸 Bloom: Jul 12 – Oct 11

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 Winnebago County

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

Soil pH

Your soil pH (6.0–6.9) is within Portulaca's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Portulaca will thrive.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Succession Planting Portulaca

3
successive plantings in your 161-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

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

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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 4" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.4" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Winnebago 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 2,093 GDD Excellent fit

Portulaca Planting Timeline — Winnebago County, IA

Portulaca Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 12 May 12 – Jun 2
Bloom June 30 Jun 30 – Sep 29

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5a

📆 Growing Season

161 days in Winnebago County

Growing Tips for Portulaca in Winnebago County

Direct sow Portulaca outdoors after April 28 in Winnebago 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 →

Frequently Asked Questions

When should I plant Portulaca in Winnebago County, IA?

Winnebago County is in Zone 5a with an average last frost of April 28. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winnebago County, IA?

Winnebago County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 6.

When should I plant Portulaca in Winnebago County County, ?

In Winnebago County County, , plant Portulaca after the last frost (around April 28) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Winnebago County County, for Portulaca?

Winnebago County County sits in USDA Zone 5a. Portulaca grows reliably in zones 3a through 11b, so it's a good fit here.

Can Portulaca grow in Winnebago County County's climate?

Yes — Portulaca grows well in Winnebago County County's temperate climate. Winnebago County County averages a 161-day frost-free season, with last frost around April 28 and first frost around October 6.

🌱

Your Winnebago County Garden Planner — Free

A 22-page printable planner built for Winnebago County (Zone 5a). 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 Winnebago County, IA. 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.