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When to plant Broccoli in Keyes, CA

Broccoli planted in Keyes between February 3 and February 24 matures in 60–90 days — well before the November 28 first frost. A second sowing from October 3 to October 17 extends the harvest into fall.

When to Plant Broccoli in Keyes, CA

Broccoli
Stanislaus County, California Zone 9b June

Stanislaus County, California gardeners: here's your June plan

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

Avg. last frost February 24
Avg. first frost November 28
Soil temp (4") 80°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Collect broccoli at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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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.

Keyes, California is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 28, giving you a growing season of approximately 277 days.

At an elevation of 2,887 feet, Stanislaus County receives approximately 15.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Broccoli during the growing season. With low rainfall, drip irrigation is essential for growing Broccoli successfully. Mulch heavily to conserve soil moisture.

Keyes, CA (Zone 9b) Year-round
277 days
Last Spring Frost February 24
277 growing days
First Fall Frost November 28

Keyes Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Broccoli Planting Risk Windows

Early Start (70% safe) ✓ Fits season (184 days to spare)
Start indoors: Jan 9 Transplant: Feb 6 🍅 Harvest: Apr 10 – May 22
Recommended (50%) ✓ Fits season (172 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: Apr 28 – Jun 9
Safe Start (90%) ✓ Fits season (137 days to spare)
Start indoors: Mar 21 Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 1

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 Keyes

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

Soil pH

Your soil pH (6.5–7.7) is more alkaline than Broccoli prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 277-day season

Sow every 6.9 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Oct 03.

Broccoli Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,287 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.1" 0" ❄️ Dormant
Feb 4.3" 3.5" 0.8" 💧 Light watering
Mar 4.3" 2.1" 2.2" 🚿 Regular watering
Apr 4.3" 1.3" 3" 🚿 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" 1.5" 2.8" 🚿 Regular watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Stanislaus 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 ~1,538 GDD — county provides 5,699 GDD Excellent fit

Broccoli Planting Timeline — Keyes, 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 October 3 Oct 3 – Oct 17

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
October Fall Sowing
November
December

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: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

277 days in Stanislaus County

Growing Tips for Broccoli in Keyes

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

Summer highs in Stanislaus County reach 94°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.

Stanislaus County receives only 15" 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 Keyes

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.

When should I plant Broccoli in Keyes, CA?

In Keyes, CA, plant Broccoli after the last frost (around February 24) and before the first frost (around November 28). Best results when soil holds above 50°F.

What growing zone is Keyes, CA for Broccoli?

Keyes sits in USDA Zone 9b. Broccoli grows reliably in zones 2a through 11b, so it's a good fit here.

Can Broccoli grow in Keyes's climate?

Yes — Broccoli grows well in Keyes's temperate climate. Keyes averages a 278-day frost-free season, with last frost around February 24 and first frost around November 28.

🌱

Your Stanislaus County Garden Planner — Free

A 22-page printable planner built for Stanislaus 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 Stanislaus County, CA. Local conditions may vary. Last updated: June 2026.