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When to plant Impatiens in Carroll County County,

Carroll County County's 174-day season only supports one Impatiens planting per year. Sow between April 29 and May 13 for the best chance at full maturity before October 13.

When to Plant Impatiens in Carroll County, IL

Carroll County, Illinois Zone 5a June

Your June game plan for Carroll County, Illinois

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

Avg. last frost April 22
Avg. first frost October 13
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Start impatiens indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

July will be here before you know it — start on
  • 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.

Carroll County, Illinois is in USDA Zone 5a. The average last spring frost is April 22 and the first fall frost is October 13, giving you a growing season of approximately 174 days.

At an elevation of 778 feet, Carroll County receives approximately 39.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Impatiens to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly
Carroll County, IL (Zone 5a) Moderate season
174 days
Last Spring Frost April 22
174 growing days
First Fall Frost October 13

Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🌸 Bloom: Jul 2 – Sep 24
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🌸 Bloom: Jul 8 – Sep 30
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Mar 8 Transplant: May 10 🌸 Bloom: Jul 19 – 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 Carroll County

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

Soil pH

Your soil pH (5.9–6.8) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

3
successive plantings in your 174-day season

Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 80 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Carroll 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 ~878 GDD — county provides 2,262 GDD Excellent fit

Impatiens Planting Timeline — Carroll County, IL

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 29 Apr 29 – May 13
Bloom July 8 Jul 8 – Sep 30

· 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 · Only during dry spells

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

174 days in Carroll County

Growing Tips for Impatiens in Carroll County

Direct sow Impatiens outdoors after April 22 in Carroll 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 Carroll County, IL?

Carroll County is in Zone 5a with an average last frost of April 22. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carroll County, IL?

Carroll County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 22 and first fall frost is October 13.

When should I plant Impatiens in Carroll County, ?

In Carroll County, , plant Impatiens after the last frost (around April 22) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Carroll County, for Impatiens?

Carroll 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 Carroll County's climate?

Yes — Impatiens grows well in Carroll County's temperate climate. Carroll County averages a 174-day frost-free season, with last frost around April 22 and first frost around October 13.

🌱

Your Carroll County Garden Planner — Free

A 22-page printable planner built for Carroll 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 Carroll County, IL. 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.