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When to Plant Impatiens in Sullivan County, PA

Sullivan County, Pennsylvania Zone 6a June

Your June gardening checklist

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

Avg. last frost May 1
Avg. first frost October 17
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Start impatiens indoors

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

To set up a strong July, finish these tasks
  • 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.

Sullivan County, Pennsylvania is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 17, giving you a growing season of approximately 169 days.

At an elevation of 560 feet, Sullivan County receives approximately 44.1 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
Sullivan County, PA (Zone 6a) Moderate season
169 days
Last Spring Frost May 1
169 growing days
First Fall Frost October 17

Sullivan County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.8

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 2 Transplant: May 4 🌸 Bloom: Jul 13 – Oct 19
Recommended (50%) ✗ May not fit
Start indoors: Mar 6 Transplant: May 8 🌸 Bloom: Jul 17 – Oct 23
Safe Start (90%) ✗ May not fit
Start indoors: Mar 22 Transplant: May 24 🌸 Bloom: Aug 2 – Nov 8

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 Sullivan County

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

Soil pH

Your soil pH (4.9–6.8) is more acidic than Impatiens prefers (6.0–6.5). Add garden lime to raise pH.

Soil Texture

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

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 169-day season

Sow every 6.9 weeks. Last sowing by Aug 03 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 3.1" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.1" 0" ❄️ Dormant
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Sullivan 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 2,577 GDD Excellent fit

Impatiens Planting Timeline — Sullivan County, PA

Impatiens Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors May 8 May 8 – May 22
Bloom July 17 Jul 17 – Oct 23

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

169 days in Sullivan County

Growing Tips for Impatiens in Sullivan County

Direct sow Impatiens outdoors after May 01 in Sullivan 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 Sullivan County, PA?

Sullivan County is in Zone 6a with an average last frost of May 1. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sullivan County, PA?

Sullivan County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 17.

🌱

Your Sullivan County Garden Planner — Free

A 22-page printable planner built for Sullivan County (Zone 6a). 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 Sullivan County, PA. 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.