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When to Plant Cauliflower in Ferry County, WA

Ferry County, Washington Zone 6b May

May in the garden — Ferry County, Washington

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

Avg. last frost May 10
Avg. first frost September 24
Soil temp (4") 48°F
Watering Critical
Pest pressure Low
Daylight 15 hrs
  1. Transplant cauliflower outside

    Frost risk is low now in Ferry County, Washington. If you've been covering beds overnight, you can stop.

June prep starts now
  • Starting indoors: cauliflower

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Cauliflower is a cool-season brassica that produces dense white, purple, or green heads called curds. It is more finicky than broccoli but rewards with a mild, nutty flavor.

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

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

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 29
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 24 Transplant: May 29 🍅 Harvest: Jul 24 – Sep 25

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 Cauliflower's growing requirements.

Soil pH

Your soil pH (5.6–6.4) overlaps with Cauliflower's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Cauliflower is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

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

How to Plant Cauliflower

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Cauliflower

2
successive plantings in your 137-day season

Sow every 6.3 weeks. Last sowing by Jun 16 to harvest before frost.

For a dedicated fall crop, sow by Jul 16.

Plant 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 Cauliflower

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

Month Cauliflower 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.

Cauliflower 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.

Cauliflower needs ~1,008 GDD — county provides 1,781 GDD Excellent fit

Cauliflower Planting Timeline — Ferry County, WA

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest July 5 Jul 5 – Sep 6
Fall Sowing July 16 Jul 16 – Jul 30

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

55–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Ferry County

Growing Tips for Cauliflower in Ferry County

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

Common pests for Cauliflower in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

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

General growing tips

Start seeds indoors 6 weeks before transplanting. Blanch white varieties by tying outer leaves over the head. Provide consistent moisture and avoid temperature extremes.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cauliflower in Ferry County, WA?

Ferry County is in Zone 6b with an average last frost of May 10. Plan your Cauliflower 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 24-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: May 2026.

Sources & credits

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