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When to Plant Romanesco in Kitsap County, WA

Kitsap County, Washington Zone 9a May

Your May gardening checklist

Here's what deserves your attention in Kitsap County, Washington this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost March 25
Avg. first frost November 5
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
To set up a strong June, finish these tasks
  • First harvests: romanesco

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Romanesco is a stunning brassica with a lime-green head composed of fractal-patterned spiraling florets. It has a nuttier, milder flavor than cauliflower.

Kitsap County, Washington is in USDA Zone 9a. The average last spring frost is March 25 and the first fall frost is November 5, giving you a growing season of approximately 225 days.

At an elevation of 264 feet, Kitsap County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Romanesco during the growing season.

Kitsap County, WA (Zone 9a) Long season
225 days
Last Spring Frost March 25
225 growing days
First Fall Frost November 5
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Kitsap County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (104 days to spare)
Start indoors: Feb 20 Transplant: Mar 20 🍅 Harvest: Jun 5 – Jul 17
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Feb 25 Transplant: Mar 25 🍅 Harvest: Jun 10 – Jul 22
Safe Start (90%) ✓ Fits season (108 days to spare)
Start indoors: Mar 18 Transplant: Apr 15 🍅 Harvest: Jul 1 – Aug 12

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 Kitsap County

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

Soil pH

Your soil pH (5.3–6.3) is more acidic than Romanesco prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Romanesco will thrive.

How to Plant Romanesco

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Romanesco

3
successive plantings in your 225-day season

Sow every 8.6 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Sep 10.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 582 gal / 100 sq ft

Monthly Watering Guide for Romanesco

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

Month Romanesco Needs Rainfall You Supplement Action
Jan 5.1" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 4.3" 4.3" 0" ✅ Rainfall sufficient
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 2" 2.3" 🚿 Regular watering
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 4.3" 6.5" 0" ✅ Rainfall sufficient
Dec 6" 0" ❄️ Dormant

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

Romanesco 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.

Romanesco needs ~1,203 GDD — county provides 3,093 GDD Excellent fit

Romanesco Planting Timeline — Kitsap County, WA

Romanesco Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 4 Mar 4 – Mar 25
Harvest June 10 Jun 10 – Jul 22
Fall Sowing September 10 Sep 10 – Sep 24

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

225 days in Kitsap County

Growing Tips for Romanesco in Kitsap County

Direct sow Romanesco outdoors after March 25 in Kitsap County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 5-7 weeks before transplanting. Provide consistent moisture and avoid temperature stress. Harvest when head is fully formed but before florets begin to separate.

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 Romanesco in Kitsap County, WA?

Kitsap County is in Zone 9a with an average last frost of March 25. Plan your Romanesco planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kitsap County, WA?

Kitsap County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is March 25 and first fall frost is November 5.

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Your Kitsap County Garden Planner — Free

A 24-page printable planner built for Kitsap County (Zone 9a). 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 Kitsap 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.