When to plant Impatiens in Sullivan County, IN
Sullivan County's 182-day season only supports one Impatiens planting per year. Sow between April 25 and May 9 for the best chance at full maturity before October 17.
When to Plant Impatiens in Sullivan County, IN
Your June planting checklist for Sullivan County, Indiana
Here's what deserves your attention in Sullivan County, Indiana this month. Everything below is tailored to Zone 6b and timed around your local frost dates.
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Get impatiens seeds going inside
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
Looking ahead to July
- First harvests: impatiens
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, Indiana is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 17, giving you a growing season of approximately 182 days.
At an elevation of 914 feet, Sullivan County receives approximately 34.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Impatiens during the growing season.
Sullivan County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7
Drainage
Well Drained
Impatiens Planting Risk Windows
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 (6.0–7.0) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.
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 excellent (4.5%) — Impatiens will thrive.
How to Plant Impatiens
Succession Planting Impatiens
Sow every 6.9 weeks. Last sowing by Aug 03 to harvest before frost.
Impatiens Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jun | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Aug | 4.3" | 4" | 0.3" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–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 Planting Timeline — Sullivan County, IN
Impatiens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 21 | Feb 21 – Mar 7 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Bloom | July 4 | Jul 4 – Oct 17 |
· 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors |
| 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 · 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
182 days in Sullivan County
Growing Tips for Impatiens in Sullivan County
Direct sow Impatiens outdoors after April 18 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 →
Impatiens in Other Locations
Frequently Asked Questions
When should I plant Impatiens in Sullivan County, IN?
Sullivan County is in Zone 6b with an average last frost of April 18. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sullivan County, IN?
Sullivan County, Indiana is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 17.
When should I plant Impatiens in Sullivan County, IN?
In Sullivan County, IN, plant Impatiens after the last frost (around April 18) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Sullivan County, IN for Impatiens?
Sullivan 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 Sullivan County's climate?
Yes — Impatiens grows well in Sullivan County's temperate climate. Sullivan County averages a 182-day frost-free season, with last frost around April 18 and first frost around October 17.
Your Sullivan County Garden Planner — Free
A 22-page printable planner built for Sullivan 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.