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When to Plant Broccoli Rabe in Whatcom County, WA

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

Whatcom County, Washington is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Broccoli Rabe during the growing season.

Whatcom County, WA (Zone 7b) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Whatcom County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 6 – Jun 10
Recommended (50%) ✓ Fits season (129 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 18 – Jun 22
Safe Start (90%) ✓ Fits season (122 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jun 17 – Jul 22

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 Whatcom County

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

Soil pH

Your soil pH (5.2โ€“6.4) is more acidic than Broccoli Rabe prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Whatcom County is excellent for Broccoli Rabe โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.7%) โ€” 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 206-day season

Sow every 4.6 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

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
Broccoli Rabe needs ~688 GDD — county provides 2,832 GDD Excellent fit

Broccoli Rabe Planting Timeline โ€” Whatcom County, WA

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 โ€“ Mar 16
Transplant Outdoors April 6 Apr 6 โ€“ Apr 20
Direct Sow March 23 Mar 23 โ€“ Apr 13
Fall Sowing August 20 Aug 20 โ€“ Sep 3
Harvest May 18 May 18 โ€“ Jun 22

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

206 days in Whatcom County

Growing Tips for Broccoli Rabe in Whatcom County

Direct sow Broccoli Rabe outdoors after April 06 in Whatcom County when soil has warmed and frost danger has passed.

Your generous 206.0-day season in Whatcom 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

Level Up Your Garden

Frequently Asked Questions

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

Whatcom County is in Zone 7b with an average last frost of April 6. Plan your Broccoli Rabe planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Whatcom County, WA?

Whatcom County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Whatcom County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Whatcom County, WA. Local conditions may vary. Last updated: April 2026.