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When to plant Impatiens in Hamilton County County,

In Hamilton County County, Impatiens is a single-season spring crop — there's no second fall window. Plant April 16–April 30 for an 75-day harvest, finishing well before the October 23 first frost.

When to Plant Impatiens in Hamilton County, IL

Hamilton County, Illinois Zone 6b June

Hamilton County, Illinois gardeners: here's your June plan

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

Avg. last frost April 9
Avg. first frost October 23
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Indoor seed-starting week for impatiens

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Basket week: impatiens

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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.

Hamilton County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 23, giving you a growing season of approximately 197 days.

At an elevation of 524 feet, Hamilton County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Impatiens during the growing season.

Annual Blooms in Summer Pollinator-friendly
Hamilton County, IL (Zone 6b) Moderate season
197 days
Last Spring Frost April 9
197 growing days
First Fall Frost October 23

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🌸 Bloom: Jun 19 – Oct 2
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Feb 12 Transplant: Apr 16 🌸 Bloom: Jun 25 – Oct 8
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🌸 Bloom: Jul 6 – Oct 19

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 Hamilton County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Impatiens will thrive.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

3
successive plantings in your 197-day season

Sow every 6.9 weeks. Last sowing by Aug 09 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 355 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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamilton 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 ~1,181 GDD — county provides 3,447 GDD Excellent fit

Impatiens Planting Timeline — Hamilton County, IL

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Bloom June 25 Jun 25 – Oct 8

· 10" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors
May
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
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 6b

📆 Growing Season

197 days in Hamilton County

Growing Tips for Impatiens in Hamilton County

Direct sow Impatiens outdoors after April 09 in Hamilton 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 Hamilton County, IL?

Hamilton County is in Zone 6b with an average last frost of April 9. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, IL?

Hamilton County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 23.

When should I plant Impatiens in Hamilton County County, ?

In Hamilton County County, , plant Impatiens after the last frost (around April 9) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Hamilton County County, for Impatiens?

Hamilton County County sits in USDA Zone 6b. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.

Can Impatiens grow in Hamilton County County's climate?

Yes — Impatiens grows well in Hamilton County County's temperate climate. Hamilton County County averages a 197-day frost-free season, with last frost around April 9 and first frost around October 23.

🌱

Your Hamilton County Garden Planner — Free

A 22-page printable planner built for Hamilton County (Zone 6b). 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 Hamilton County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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