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When to Plant Broccoli in San Bernardino County, CA

San Bernardino County, California Zone 9a April

April in San Bernardino County, California — your action list

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 24
Avg. first frost November 25
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 12.9 hrs
  1. Harvest broccoli as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

May prep starts now
  • First harvests: broccoli

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Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

San Bernardino County, California is in USDA Zone 9a. The average last spring frost is February 24 and the first fall frost is November 25, giving you a growing season of approximately 274 days.

At an elevation of 1,012 feet, San Bernardino County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Broccoli may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Broccoli successfully. Mulch heavily to conserve soil moisture.

San Bernardino County, CA (Zone 9a) Year-round
274 days
Last Spring Frost February 24
274 growing days
First Fall Frost November 25
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San Bernardino County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: Apr 17 – May 29
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: Apr 28 – Jun 9
Safe Start (90%) ✓ Fits season (172 days to spare)
Start indoors: Feb 7 Transplant: Mar 7 🍅 Harvest: May 9 – Jun 20

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 San Bernardino County

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

Soil pH

Your soil pH (5.9–7.2) overlaps with Broccoli's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Broccoli.

How to Plant Broccoli

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

5
successive plantings in your 274-day season

Sow every 6.9 weeks. Last sowing by Aug 27 to harvest before frost.

For a dedicated fall crop, sow by Sep 30.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,179 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Broccoli

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

Month Broccoli Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 4.3" 3.8" 0.5" 💧 Light watering
Mar 4.3" 2.2" 2.1" 💧 Light watering
Apr 4.3" 1.5" 2.8" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.7" 3.6" 🚿 Regular watering
Nov 4.3" 1.7" 2.6" 🚿 Regular watering
Dec 3" 0" ❄️ Dormant

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

Broccoli 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 needs ~1,706 GDD — county provides 6,256 GDD Excellent fit

Broccoli Planting Timeline — San Bernardino County, CA

Broccoli Planting Calendar

Activity When Date Range
Start Indoors January 27 Jan 27 – Feb 10
Transplant Outdoors February 24 Feb 24 – Mar 10
Direct Sow February 3 Feb 3 – Feb 24
Harvest April 28 Apr 28 – Jun 9
Fall Sowing September 30 Sep 30 – Oct 14

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

274 days in San Bernardino County

Growing Tips for Broccoli in San Bernardino County

Direct sow Broccoli outdoors after February 24 in San Bernardino County when soil has warmed and frost danger has passed.

Summer highs in San Bernardino County reach 97°F — grow Broccoli as a spring or fall crop. Use shade cloth if planting in summer.

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

San Bernardino County receives only 17" of rain annually. Broccoli needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Recommended Broccoli Varieties for San Bernardino County

Heat-tolerant broccoli — plant as early spring or fall crop

Arcadia Marathon Green Magic

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in San Bernardino County, CA?

San Bernardino County is in Zone 9a with an average last frost of February 24. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Bernardino County, CA?

San Bernardino County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 24 and first fall frost is November 25.

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Your San Bernardino County Garden Planner — Free

A 24-page printable planner built for San Bernardino 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 San Bernardino County, CA. Local conditions may vary. Last updated: April 2026.

Sources & credits

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