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When to Plant Bok Choy in Calaveras County, CA

Calaveras County, California Zone 9a May

What to do in May

A quick May briefing for Calaveras County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 8
Avg. first frost November 12
Soil temp (4") 68°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Sow bok choy in trays indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. It's harvest week for bok choy

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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

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Bok choy is a Chinese cabbage variety with crisp white stalks and dark green leaves. It is a fast-growing cool-season crop ideal for stir-fries and soups.

Calaveras County, California is in USDA Zone 9a. The average last spring frost is April 8 and the first fall frost is November 12, giving you a growing season of approximately 218 days.

At an elevation of 2,363 feet, Calaveras County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Bok Choy to ensure they mature before fall.

Calaveras County, CA (Zone 9a) Long season
218 days
Last Spring Frost April 8
218 growing days
First Fall Frost November 12
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Calaveras County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (169 days to spare)
Start indoors: Feb 2 Transplant: Mar 2 🍅 Harvest: Apr 13 – May 18
Recommended (50%) ✓ Fits season (141 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: May 20 – Jun 24
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jun 19 – Jul 24

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 Calaveras County

How your county's soil matches Bok Choy's growing requirements.

Soil pH

Your soil pH (6.5–7.6) overlaps with Bok Choy's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Calaveras County is excellent for Bok Choy — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Bok Choy.

How to Plant Bok Choy

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 Bok Choy

6
successive plantings in your 218-day season

Sow every 4.6 weeks. Last sowing by Sep 13 to harvest before frost.

For a dedicated fall crop, sow by Sep 17.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 508 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Bok Choy

Bok Choy needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Bok Choy Needs Rainfall You Supplement Action
Jan 5.4" 0" ❄️ Dormant
Feb 4.8" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 3" 2.4" 0.6" 💧 Light watering
May 3" 0.7" 2.3" 🚿 Regular watering
Jun 3" 0.2" 2.8" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.3" 2.7" 🚿 Regular watering
Oct 3" 1" 2" 🚿 Regular watering
Nov 3" 2.3" 0.7" 💧 Light watering
Dec 3.9" 0" ❄️ Dormant

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

Bok Choy 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.

Bok Choy needs ~612 GDD — county provides 2,670 GDD Excellent fit

Bok Choy Planting Timeline — Calaveras County, CA

Bok Choy Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow March 18 Mar 18 – Apr 8
Harvest May 20 May 20 – Jun 24
Fall Sowing September 17 Sep 17 – Oct 1

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

218 days in Calaveras County

Growing Tips for Bok Choy in Calaveras County

Direct sow Bok Choy outdoors after April 08 in Calaveras County when soil has warmed and frost danger has passed.

Your generous 218.0-day season in Calaveras County allows multiple plantings of Bok Choy. Sow every 20.0 days for continuous harvest.

Common pests for Bok Choy 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 for best results. Keep soil consistently moist. Harvest whole heads or cut outer leaves for a cut-and-come-again approach.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bok Choy in Calaveras County, CA?

Calaveras County is in Zone 9a with an average last frost of April 8. Plan your Bok Choy planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calaveras County, CA?

Calaveras County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 8 and first fall frost is November 12.

🌱

Your Calaveras County Garden Planner — Free

A 24-page printable planner built for Calaveras 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 Calaveras 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.