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When to plant Impatiens in Cedar County, IA

Cedar County's 182-day season only supports one Impatiens planting per year. Sow between April 24 and May 8 for the best chance at full maturity before October 16.

When to Plant Impatiens in Cedar County, IA

Cedar County, Iowa Zone 5a July

This month in Cedar County, Iowa

Each item below is timed to Cedar County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 17
Avg. first frost October 16
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. It's harvest week for impatiens

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

Coming up in August — start thinking about
  • First harvests: impatiens

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Impatiens (Impatiens walleriana) are the go-to annual for shaded beds and containers. They produce a continuous carpet of flat-faced blooms from transplant until frost, needing little deadheading. Their preference for consistent moisture and part-shade makes them ideal under trees and along north-facing borders.

Cedar County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 1,112 feet, Cedar County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Impatiens during the growing season.

Annual Blooms in Summer Pollinator-friendly
Cedar County, IA (Zone 5a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Cedar County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🌸 Bloom: Jun 28 – Sep 20
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Feb 20 Transplant: Apr 24 🌸 Bloom: Jul 3 – Sep 25
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Mar 13 Transplant: May 15 🌸 Bloom: Jul 24 – Oct 16

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 Cedar County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Impatiens.

Organic Matter

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

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

3
successive plantings in your 182-day season

Sow every 6.9 weeks. Last sowing by Aug 02 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 688 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Impatiens

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

Month Impatiens Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cedar County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Impatiens 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.

Impatiens needs ~1,029 GDD — county provides 2,775 GDD Excellent fit

Impatiens Planting Timeline — Cedar County, IA

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors April 24 Apr 24 – May 8
Bloom July 3 Jul 3 – Sep 25

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

182 days in Cedar County

Growing Tips for Impatiens in Cedar County

Direct sow Impatiens outdoors after April 17 in Cedar County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost at 70–75°F; germination requires light — do not cover seeds. Transplant after last frost once nights consistently exceed 50°F. Water regularly — wilting causes bud drop and they rarely fully recover the same flush. Watch for impatiens downy mildew (IDM); consider New Guinea impatiens as a resistant alternative in affected regions. Pinch tips at planting to encourage branching.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Impatiens in Cedar County, IA?

Cedar County is in Zone 5a with an average last frost of April 17. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cedar County, IA?

Cedar County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.

When should I plant Impatiens in Cedar County, IA?

In Cedar County, IA, plant Impatiens after the last frost (around April 17) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Cedar County, IA for Impatiens?

Cedar County sits in USDA Zone 5a. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.

Can Impatiens grow in Cedar County's climate?

Yes — Impatiens grows well in Cedar County's temperate climate. Cedar County averages a 182-day frost-free season, with last frost around April 17 and first frost around October 16.

🌱

Your Cedar County Garden Planner — Free

A 22-page printable planner built for Cedar 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 Cedar County, IA. 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.