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When to Plant Impatiens in Ferry County, WA

Ferry County, Washington Zone 6b July

Your July planting checklist for Ferry County, Washington

We've pulled the most time-sensitive tasks for Ferry County, Washington this July and put them front and centre. Tackle them in order.

Avg. last frost May 10
Avg. first frost September 24
Soil temp (4") 65°F
Watering Critical
Pest pressure High
Daylight 15.5 hrs
  1. Start impatiens under lights

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

  2. Harvest impatiens as they ripen

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

August will be here before you know it — start on
  • 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.

Ferry County, Washington is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 24, giving you a growing season of approximately 137 days.

At an elevation of 3,990 feet, Ferry County receives approximately 18.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Impatiens to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Impatiens successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly
Ferry County, WA (Zone 6b) Short season
137 days
Last Spring Frost May 10
137 growing days
First Fall Frost September 24

Ferry County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.4

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 7 Transplant: May 9 🌸 Bloom: Jul 18 – Oct 31
Recommended (50%) ✗ May not fit
Start indoors: Mar 15 Transplant: May 17 🌸 Bloom: Jul 26 – Nov 8
Safe Start (90%) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 5 🌸 Bloom: Aug 14 – Nov 27

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 Ferry County

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

Soil pH

Your soil pH (5.6–6.4) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Impatiens.

Organic Matter

Organic matter is excellent (4.6%) — Impatiens will thrive.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

2
successive plantings in your 137-day season

Sow every 6.9 weeks. Last sowing by Jul 11 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 905 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 2.8" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 1.2" 3.1" 🚿 Regular watering
Jun 4.3" 0.7" 3.6" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.7" 3.6" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Ferry 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 ~878 GDD — county provides 1,781 GDD Excellent fit

Impatiens Planting Timeline — Ferry County, WA

Impatiens Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 17 May 17 – May 31
Bloom July 26 Jul 26 – Nov 8

· 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 Bloom
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Ferry County

Growing Tips for Impatiens in Ferry County

Direct sow Impatiens outdoors after May 10 in Ferry County when soil has warmed and frost danger has passed.

Ferry County receives only 18" of rain annually. Impatiens needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Ferry County, WA?

Ferry County is in Zone 6b with an average last frost of May 10. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ferry County, WA?

Ferry County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 24.

🌱

Your Ferry County Garden Planner — Free

A 22-page printable planner built for Ferry 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 Ferry County, WA. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.