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When to Plant Begonias in Stevens County, WA

Stevens County, Washington Zone 6b June

This month in Stevens County, Washington

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Stevens County, Washington.

Avg. last frost May 10
Avg. first frost September 24
Soil temp (4") 65°F
Watering Critical
Pest pressure High
Daylight 15.9 hrs
A few tasks this June that'll pay off in July
  • Starting indoors: begonias
  • First harvests: begonias

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Wax begonias (Begonia × semperflorens) are the workhorse shade bedding plant of American horticulture, offering continuous bloom from transplant to hard frost. Bronze or green-leaved varieties perform well from deep shade to full sun (in northern zones) and tolerate summer humidity better than most cool- season flowers. A staple of mass plantings, containers, and window boxes.

Stevens 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 1,751 feet, Stevens County receives approximately 24.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Begonias to ensure they mature before fall.

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

Stevens County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.3

Drainage

Well Drained

Begonias Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 21 Transplant: May 9 🌸 Bloom: Jul 18 – Oct 24
Recommended (50%) ✗ May not fit
Start indoors: Mar 1 Transplant: May 17 🌸 Bloom: Jul 26 – Nov 1
Safe Start (90%) ✗ May not fit
Start indoors: Mar 20 Transplant: Jun 5 🌸 Bloom: Aug 14 – Nov 20

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 Stevens County

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

Soil pH

Your soil pH (5.3–6.3) overlaps with Begonias's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Begonias will thrive.

How to Plant Begonias

8"
Between Plants
10"
Between Rows

Succession Planting Begonias

2
successive plantings in your 137-day season

Sow every 8 weeks. Last sowing by Jun 26 to harvest before frost.

Begonias Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 307 gal / 100 sq ft

Monthly Watering Guide for Begonias

Begonias needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Begonias Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 1.3" 3" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.9" 3.4" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 4.2" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Stevens County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Begonias 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.

Begonias needs ~980 GDD — county provides 1,678 GDD Excellent fit

Begonias Planting Timeline — Stevens County, WA

Begonias Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors May 17 May 17 – May 31
Bloom July 26 Jul 26 – Nov 1

· 8" apart · Rows 10" 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 · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Stevens County

Growing Tips for Begonias in Stevens County

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

Stevens County receives only 24" of rain annually. Begonias needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 10–12 weeks before last frost — seed is dust-fine; surface-sow on moist mix under lights, do not cover. Bottom heat (70–75°F) speeds germination. Transplant after frost; begonias are not direct-sown in practice. Pinch seedlings once for branching. Keep soil evenly moist; avoid waterlogged conditions. Bronze-leaf types tolerate more sun; green- leaf types prefer shade to part-sun.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Begonias in Stevens County, WA?

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

What planting zone is Stevens County, WA?

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

🌱

Your Stevens County Garden Planner — Free

A 22-page printable planner built for Stevens 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 Stevens County, WA. 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.