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When to Plant Broccoli Rabe in Butte County, CA

Butte County, California Zone 9b May

May in the garden — Butte County, California

Your garden in Butte County, California is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 20
Avg. first frost November 10
Soil temp (4") 75°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Fire up the seed-starting tray: broccoli rabe

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

A few tasks this May that'll pay off in June
  • First harvests: broccoli rabe

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

Butte County, California is in USDA Zone 9b. The average last spring frost is April 20 and the first fall frost is November 10, giving you a growing season of approximately 204 days.

At an elevation of 144 feet, Butte County receives approximately 44.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Broccoli Rabe during the growing season.

Butte County, CA (Zone 9b) Long season
204 days
Last Spring Frost April 20
204 growing days
First Fall Frost November 10

Butte County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (122 days to spare)
Start indoors: Feb 26 Transplant: Mar 26 🍅 Harvest: May 7 – Jun 11
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Mar 23 Transplant: Apr 20 🍅 Harvest: Jun 1 – Jul 6
Safe Start (90%) ✓ Fits season (127 days to spare)
Start indoors: Apr 26 Transplant: May 24 🍅 Harvest: Jul 5 – Aug 9

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 Butte County

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

Soil pH

Your soil pH (6.8–7.7) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Broccoli Rabe.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Broccoli Rabe.

How to Plant Broccoli Rabe

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 Broccoli Rabe

6
successive plantings in your 204-day season

Sow every 4.6 weeks. Last sowing by Sep 11 to harvest before frost.

For a dedicated fall crop, sow by Sep 15.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 256 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 9.7" 0" ❄️ Dormant
Feb 9.9" 0" ❄️ Dormant
Mar 6.9" 0" ❄️ Dormant
Apr 3.5" 3" 0.5" 💧 Light watering
May 3.5" 1.1" 2.4" 🚿 Regular watering
Jun 3.5" 0.2" 3.3" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.4" 3.1" 🚿 Regular watering
Oct 3.5" 2.1" 1.4" 💧 Light watering
Nov 3.5" 3.7" 0" ✅ Rainfall sufficient
Dec 7.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Butte 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 3,570 GDD Excellent fit

Broccoli Rabe Planting Timeline — Butte County, CA

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow March 30 Mar 30 – Apr 20
Harvest June 1 Jun 1 – Jul 6
Fall Sowing September 15 Sep 15 – Sep 29

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

204 days in Butte County

Growing Tips for Broccoli Rabe in Butte County

Direct sow Broccoli Rabe outdoors after April 20 in Butte County when soil has warmed and frost danger has passed.

Your generous 204.0-day season in Butte 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 Butte County, CA?

Butte County is in Zone 9b with an average last frost of April 20. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Butte County, CA?

Butte County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 20 and first fall frost is November 10.

🌱

Your Butte County Garden Planner — Free

A 24-page printable planner built for Butte County (Zone 9b). 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 Butte County, CA. 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.