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When to plant Impatiens in Kankakee County County,

Kankakee County County sits in cold Zone 5b. Plant Impatiens April 27–May 11 for the single annual harvest; the October 14 first frost closes the window.

When to Plant Impatiens in Kankakee County, IL

Kankakee County, Illinois Zone 5b June

June to-do list for Kankakee County, Illinois

Here's what deserves your attention in Kankakee County, Illinois this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost April 20
Avg. first frost October 14
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Indoor seed-starting week for impatiens

    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.

Before July arrives, get these ready
  • 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.

Kankakee County, Illinois is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.

At an elevation of 1,113 feet, Kankakee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Impatiens during the growing season.

Annual Blooms in Summer Pollinator-friendly
Kankakee County, IL (Zone 5b) Moderate season
177 days
Last Spring Frost April 20
177 growing days
First Fall Frost October 14
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Kankakee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🌸 Bloom: Jul 1 – Sep 30
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🌸 Bloom: Jul 6 – Oct 5
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Mar 14 Transplant: May 16 🌸 Bloom: Jul 25 – Oct 24

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 Kankakee County

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

Soil pH

Your soil pH (6.1–6.8) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) — Impatiens will thrive.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

3
successive plantings in your 177-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 319 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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Kankakee 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 ~928 GDD — county provides 2,433 GDD Excellent fit

Impatiens Planting Timeline — Kankakee County, IL

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 – Mar 9
Transplant Outdoors April 27 Apr 27 – May 11
Bloom July 6 Jul 6 – Oct 5

· 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 Bloom
November
December
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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 5b

📆 Growing Season

177 days in Kankakee County

Growing Tips for Impatiens in Kankakee County

Direct sow Impatiens outdoors after April 20 in Kankakee 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 Kankakee County, IL?

Kankakee County is in Zone 5b with an average last frost of April 20. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kankakee County, IL?

Kankakee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 14.

When should I plant Impatiens in Kankakee County County, ?

In Kankakee County County, , plant Impatiens after the last frost (around April 20) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Kankakee County County, for Impatiens?

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

Can Impatiens grow in Kankakee County County's climate?

Yes — Impatiens grows well in Kankakee County County's temperate climate. Kankakee County County averages a 177-day frost-free season, with last frost around April 20 and first frost around October 14.

🌱

Your Kankakee County Garden Planner — Free

A 22-page printable planner built for Kankakee 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 Kankakee 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.