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When to Plant Pac Choi in San Benito County, CA

San Benito County, California Zone 9a April

Your April game plan for San Benito County, California

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 21
Avg. first frost November 29
Soil temp (4") 68°F
Watering Critical
Pest pressure High
Daylight 12.9 hrs
  1. Pick pac choi

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

Get ahead of May
  • First harvests: pac choi

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Pac choi (baby bok choy) is a compact variety of Chinese cabbage with tender leaves and crisp stems. It grows quickly and is ideal for containers and small spaces.

San Benito County, California is in USDA Zone 9a. The average last spring frost is February 21 and the first fall frost is November 29, giving you a growing season of approximately 281 days.

At an elevation of 149 feet, San Benito County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Pac Choi during the growing season. With low rainfall, drip irrigation is essential for growing Pac Choi successfully. Mulch heavily to conserve soil moisture.

San Benito County, CA (Zone 9a) Year-round
281 days
Last Spring Frost February 21
281 growing days
First Fall Frost November 29

San Benito County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (220 days to spare)
Start indoors: Jan 8 Transplant: Feb 5 🍅 Harvest: Mar 19 – Apr 16
Recommended (50%) ✓ Fits season (211 days to spare)
Start indoors: Jan 24 Transplant: Feb 21 🍅 Harvest: Apr 4 – May 2
Safe Start (90%) ✓ Fits season (187 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: May 20 – Jun 17

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 Benito County

How your county's soil matches Pac Choi's growing requirements.

Soil pH

Your soil pH (6.5–7.4) is within Pac Choi's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Pac Choi.

How to Plant Pac Choi

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 Pac Choi

8
successive plantings in your 281-day season

Sow every 4.6 weeks. Last sowing by Oct 05 to harvest before frost.

For a dedicated fall crop, sow by Oct 04.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.2″/week
You supply
1.6″/week
Watering frequency 2-3 times/week
Season total 3,935 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Pac Choi

Pac Choi needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Pac Choi Needs Rainfall You Supplement Action
Jan 2.5" 0" ❄️ Dormant
Feb 6.5" 2.6" 3.9" 🚿 Regular watering
Mar 6.5" 2.2" 4.3" 🚿 Regular watering
Apr 6.5" 1.1" 5.4" 🚿 Regular watering
May 6.5" 0.3" 6.2" 🚿 Regular watering
Jun 6.5" 0.1" 6.4" 🚿 Regular watering
Jul 6.5" 0" 6.5" 🚿 Regular watering
Aug 6.5" 0" 6.5" 🚿 Regular watering
Sep 6.5" 0.1" 6.4" 🚿 Regular watering
Oct 6.5" 0.5" 6" 🚿 Regular watering
Nov 6.5" 1.3" 5.2" 🚿 Regular watering
Dec 2.3" 0" ❄️ Dormant

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

Pac Choi 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.

Pac Choi needs ~974 GDD — county provides 5,781 GDD Excellent fit

Pac Choi Planting Timeline — San Benito County, CA

Pac Choi Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 – Feb 7
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow January 31 Jan 31 – Feb 21
Harvest April 4 Apr 4 – May 2
Fall Sowing October 4 Oct 4 – Oct 18

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

40–55 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

281 days in San Benito County

Growing Tips for Pac Choi in San Benito County

Direct sow Pac Choi outdoors after February 21 in San Benito County when soil has warmed and frost danger has passed.

Your generous 282.0-day season in San Benito County allows multiple plantings of Pac Choi. Sow every 20.0 days for continuous harvest.

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

San Benito County receives only 13" of rain annually. Pac Choi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in spring or fall. Grows best in cool weather. Space 6 inches apart for baby pac choi. Harvest whole plants or cut outer leaves as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pac Choi in San Benito County, CA?

San Benito County is in Zone 9a with an average last frost of February 21. Plan your Pac Choi planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Benito County, CA?

San Benito County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 21 and first fall frost is November 29.

🌱

Your San Benito County Garden Planner — Free

A 24-page printable planner built for San Benito 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 Benito 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.