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When to plant Pansy in Union County County,

Union County County's short 171-day growing season means one Pansy planting between April 23 and May 7. No fall crop in Zone 5b.

When to Plant Pansy in Union County, IA

Union County, Iowa Zone 5b June

Top priorities for Union County, Iowa gardeners in June

A quick June briefing for Union County, Iowa gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 23
Avg. first frost October 11
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Pick pansy

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

Coming up in July — start thinking about
  • 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.

Union County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.

At an elevation of 1,311 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Pansy to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Good for cutting
Union County, IA (Zone 5b) Moderate season
171 days
Last Spring Frost April 23
171 growing days
First Fall Frost October 11

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Pansy Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Feb 6 Transplant: Apr 17 🌸 Bloom: Jun 12 – Aug 14
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🌸 Bloom: Jun 18 – Aug 20
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Feb 28 Transplant: May 9 🌸 Bloom: Jul 4 – Sep 5

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 Union County

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

Soil pH

Your soil pH (6.3–7.3) 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 Union County is excellent for Pansy — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) — Pansy will thrive.

How to Plant Pansy

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

Succession Planting Pansy

2
successive plantings in your 171-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
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 64 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 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union 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 ~980 GDD — county provides 2,094 GDD Excellent fit

Pansy Planting Timeline — Union County, IA

Pansy Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 23 Apr 23 – May 7
Bloom June 18 Jun 18 – Aug 20

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 · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 5.4–6.2 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

171 days in Union County

Growing Tips for Pansy in Union County

Direct sow Pansy outdoors after April 23 in Union 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 Union County, IA?

Union County is in Zone 5b with an average last frost of April 23. Plan your Pansy planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, IA?

Union County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 11.

When should I plant Pansy in Union County County, ?

In Union County County, , plant Pansy after the last frost (around April 23) and before the first frost (around October 11). Best results when soil holds above 50°F.

What growing zone is Union County County, for Pansy?

Union County 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 Union County County's climate?

Yes — Pansy grows well in Union County County's temperate climate. Union County County averages a 171-day frost-free season, with last frost around April 23 and first frost around October 11.

🌱

Your Union County Garden Planner — Free

A 22-page printable planner built for Union 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 Union 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.