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When to plant Pansy in Johnson County, IA

Plant Pansy in Johnson County during the brief April 24–May 8 window. With 170 frost-free days, fall plantings can't mature before October 11.

When to Plant Pansy in Johnson County, IA

Johnson County, Iowa Zone 5b June

Top priorities for Johnson County, Iowa gardeners in June

Your garden in Johnson County, Iowa is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 24
Avg. first frost October 11
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. It's harvest week for pansy

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

Before July arrives, get these ready
  • Starting indoors: pansy
  • First harvests: pansy

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Pansies (Viola × wittrockiana) are beloved cool-season annuals offering some of the widest color range in the annual garden. Their cheerful "faces" appear in early spring — or even late winter in mild climates — and hold up remarkably well through frosts. Heat causes them to go leggy and stop blooming; replace with warm-season annuals once daytime temps exceed 70°F.

Johnson County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 1,204 feet, Johnson County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Pansy during the growing season.

Annual Blooms in Spring Pollinator-friendly Good for cutting
Johnson County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Johnson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Pansy Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Feb 5 Transplant: Apr 16 🌸 Bloom: Jun 11 – Aug 13
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Feb 13 Transplant: Apr 24 🌸 Bloom: Jun 19 – Aug 21
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Feb 27 Transplant: May 8 🌸 Bloom: Jul 3 – Sep 4

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 Pansy's growing requirements.

Soil pH

Your soil pH (6.2–7.3) is more alkaline than Pansy prefers (5.4–6.2). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Pansy.

How to Plant Pansy

0.3"
Planting Depth
7"
Between Plants
10"
Between Rows

Succession Planting Pansy

2
successive plantings in your 170-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Pansy Water Budget

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

Monthly Watering Guide for Pansy

Pansy needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Pansy Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 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.

Pansy 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.

Pansy needs ~1,100 GDD — county provides 2,337 GDD Excellent fit

Pansy Planting Timeline — Johnson County, IA

Pansy Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors April 24 Apr 24 – May 8
Bloom June 19 Jun 19 – Aug 21

Plant 0.3" deep · 7" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 5.4–6.2 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Johnson County

Growing Tips for Pansy in Johnson County

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

General growing tips

Start indoors 10-12 weeks before last frost for spring transplants. In zones 6+, fall planting (8-10 weeks before first frost) gives overwintering plants that bloom earliest in spring. Plant in full sun in cool weather; afternoon shade helps extend bloom in zones 7-8. Deadhead to prevent premature seed set. Shear back by one-third when plants go leggy to extend the season.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pansy in Johnson County, IA?

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

What planting zone is Johnson County, IA?

Johnson County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.

When should I plant Pansy in Johnson County, IA?

In Johnson County, IA, plant Pansy after the last frost (around April 24) and before the first frost (around October 11). Best results when soil holds above 50°F.

What growing zone is Johnson County, IA for Pansy?

Johnson County sits in USDA Zone 5b. Pansy grows reliably in zones 3a through 10b, so it's a good fit here.

Can Pansy grow in Johnson County's climate?

Yes — Pansy grows well in Johnson County's temperate climate. Johnson County averages a 170-day frost-free season, with last frost around April 24 and first frost around October 11.

🌱

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, 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.