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When to Plant Alliums in Ferry County, WA

Ferry County, Washington Zone 6b June

Your June gardening checklist

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

Avg. last frost May 10
Avg. first frost September 24
Soil temp (4") 56°F
Watering Critical
Pest pressure High
Daylight 15.9 hrs

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Ornamental alliums (Allium spp.) bridge the gap between spring and summer with their striking globe-shaped flower heads in shades of purple, violet, white, and pink. Blooming after tulips have faded, they extend the spring display well into early summer. 'Gladiator', 'Globemaster', and 'Purple Sensation' produce softball-sized heads on 18–36 inch stems, while smaller species create charming accents at border fronts. Deer and rodents shun them completely due to the characteristic onion scent. Dried seed heads provide architectural interest into fall.

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 Alliums to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Alliums successfully. Mulch heavily to conserve soil moisture.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
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

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Transplant: May 2 🌸 Bloom: May 30 – Jun 27
Recommended (50%) ✓ Fits season (81 days to spare)
Transplant: May 10 🌸 Bloom: Jun 7 – Jul 5
Safe Start (90%) ✓ Fits season (80 days to spare)
Transplant: May 29 🌸 Bloom: Jun 26 – Jul 24

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 Alliums's growing requirements.

Soil pH

Your soil pH (5.6–6.4) is within Alliums's preferred range (5.5–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Alliums.

Organic Matter

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

How to Plant Alliums

5"
Planting Depth
7"
Between Plants
8"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Alliums

5
successive plantings in your 137-day season

Sow every 3.1 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Aug 13.

Alliums Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 112 gal / 100 sq ft

Monthly Watering Guide for Alliums

Alliums needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Alliums 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 2.2" 1.2" 1" 💧 Light watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.7" 1.5" 🚿 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.

Alliums 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.

Alliums needs ~455 GDD — county provides 1,781 GDD Excellent fit

Alliums Planting Timeline — Ferry County, WA

Alliums Planting Calendar

Activity When Date Range
Bloom September 10 Sep 10 – Oct 8
Fall Sowing August 13 Aug 13 – Aug 27

Plant 5" deep · 7" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July
August Fall Sowing
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

28–42 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Ferry County

Growing Tips for Alliums in Ferry County

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

Your generous 137.0-day season in Ferry County allows multiple plantings of Alliums. Sow every 14.0 days for continuous harvest.

Common pests for Alliums in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

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

General growing tips

Plant bulbs in fall, 3–4 times as deep as the bulb diameter (typically 4–6 inches for large types, 3 inches for small species). Space 6–8 inches apart for standard cultivars. Foliage often looks untidy as it dies back before bloom — plant around perennials that will conceal the yellowing leaves. Excellent drainage is essential; alliums rot in wet soils. Leave bulbs in place for naturalization; divide every 3–4 years when clusters become congested. Deadhead spent globes or leave for ornamental seedheads and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Beans
  • Peas

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Alliums in Ferry County, WA?

Ferry County is in Zone 6b with an average last frost of May 10. Plan your Alliums 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: June 2026.

Sources & credits

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