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When to plant Impatiens in Cole County, MO

Cole County sits in cold Zone 6b. Plant Impatiens April 14–April 28 for the single annual harvest; the October 28 first frost closes the window.

When to Plant Impatiens in Cole County, MO

Cole County, Missouri Zone 6b June

Your June game plan for Cole County, Missouri

Your Cole County, Missouri garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 7
Avg. first frost October 28
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Time to start impatiens inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Basket week: impatiens

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Looking ahead to July
  • 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.

Cole County, Missouri is in USDA Zone 6b. The average last spring frost is April 7 and the first fall frost is October 28, giving you a growing season of approximately 204 days.

At an elevation of 614 feet, Cole County receives approximately 39.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Impatiens during the growing season.

Annual Blooms in Summer Pollinator-friendly
Cole County, MO (Zone 6b) Long season
204 days
Last Spring Frost April 7
204 growing days
First Fall Frost October 28

Cole County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.9

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Feb 3 Transplant: Apr 7 🌸 Bloom: Jun 16 – Sep 29
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🌸 Bloom: Jun 23 – Oct 6
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🌸 Bloom: Jul 8 – Oct 21

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 Cole County

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

Soil pH

Your soil pH (5.4–6.9) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Impatiens.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Impatiens.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

4
successive plantings in your 204-day season

Sow every 6.9 weeks. Last sowing by Aug 14 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cole 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 ~1,080 GDD — county provides 3,264 GDD Excellent fit

Impatiens Planting Timeline — Cole County, MO

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Bloom June 23 Jun 23 – Oct 6

· 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 · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

204 days in Cole County

Growing Tips for Impatiens in Cole County

Direct sow Impatiens outdoors after April 07 in Cole 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 Cole County, MO?

Cole County is in Zone 6b with an average last frost of April 7. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cole County, MO?

Cole County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 7 and first fall frost is October 28.

When should I plant Impatiens in Cole County, MO?

In Cole County, MO, plant Impatiens after the last frost (around April 7) and before the first frost (around October 28). Best results when soil holds above 50°F.

What growing zone is Cole County, MO for Impatiens?

Cole 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 Cole County's climate?

Yes — Impatiens grows well in Cole County's temperate climate. Cole County averages a 204-day frost-free season, with last frost around April 7 and first frost around October 28.

🌱

Your Cole County Garden Planner — Free

A 22-page printable planner built for Cole 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 Cole County, MO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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