Blog

When to Plant Broccoli Rabe in Snohomish County, WA

Snohomish County, Washington Zone 8b May

May to-do list for Snohomish County, Washington

May is a pivotal month for Snohomish County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 25
Avg. first frost November 2
Soil temp (4") 70°F
Watering High
Pest pressure High
Daylight 15 hrs
  1. Collect broccoli rabe at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of June
  • First harvests: broccoli rabe

Instant PDF download. No spam, unsubscribe any time.

Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

Snohomish County, Washington is in USDA Zone 8b. The average last spring frost is March 25 and the first fall frost is November 2, giving you a growing season of approximately 222 days.

At an elevation of 230 feet, Snohomish County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Broccoli Rabe during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Broccoli Rabe root diseases.

Snohomish County, WA (Zone 8b) Long season
222 days
Last Spring Frost March 25
222 growing days
First Fall Frost November 2

Snohomish County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (146 days to spare)
Start indoors: Feb 12 Transplant: Mar 19 🍅 Harvest: Apr 30 – Jun 4
Recommended (50%) ✓ Fits season (145 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 6 – Jun 10
Safe Start (90%) ✓ Fits season (144 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: May 30 – Jul 4

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 Snohomish County

How your county's soil matches Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (5.7–6.8) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.4%) — Broccoli Rabe will thrive.

How to Plant Broccoli Rabe

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 Broccoli Rabe

6
successive plantings in your 222-day season

Sow every 4.6 weeks. Last sowing by Sep 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Broccoli Rabe

Broccoli Rabe needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Rabe Needs Rainfall You Supplement Action
Jan 7.7" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 3.5" 5" 0" ✅ Rainfall sufficient
Apr 3.5" 3.6" 0" ✅ Rainfall sufficient
May 3.5" 2.6" 0.9" 💧 Light watering
Jun 3.5" 1.6" 1.9" 🚿 Regular watering
Jul 3.5" 0.7" 2.8" 🚿 Regular watering
Aug 3.5" 1" 2.5" 🚿 Regular watering
Sep 3.5" 2" 1.5" 💧 Light watering
Oct 3.5" 4.2" 0" ✅ Rainfall sufficient
Nov 3.5" 8" 0" ✅ Rainfall sufficient
Dec 8.5" 0" ❄️ Dormant

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

Broccoli Rabe 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.

Broccoli Rabe needs ~875 GDD — county provides 3,885 GDD Excellent fit

Broccoli Rabe Planting Timeline — Snohomish County, WA

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 11 Mar 11 – Apr 1
Harvest May 6 May 6 – Jun 10
Fall Sowing August 24 Aug 24 – Sep 7

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 Direct Sow
May Harvest
June Harvest
July
August Fall Sowing
September Fall Sowing
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

222 days in Snohomish County

Growing Tips for Broccoli Rabe in Snohomish County

Direct sow Broccoli Rabe outdoors after March 25 in Snohomish County when soil has warmed and frost danger has passed.

Your generous 222.0-day season in Snohomish County allows multiple plantings of Broccoli Rabe. Sow every 20.0 days for continuous harvest.

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

General growing tips

Direct sow in spring or fall. Harvest when small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Broccoli Rabe in Snohomish County, WA?

Snohomish County is in Zone 8b with an average last frost of March 25. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Snohomish County, WA?

Snohomish County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 25 and first fall frost is November 2.

🌱

Your Snohomish County Garden Planner — Free

A 24-page printable planner built for Snohomish County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Snohomish 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.