When to Plant Bok Choy in Alameda County, CA
May in the garden — Alameda County, California
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Alameda County, California.
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.
Alameda County, California is in USDA Zone 10a. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.
At an elevation of 379 feet, Alameda County receives approximately 16.4 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Bok Choy may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Bok Choy successfully. Mulch heavily to conserve soil moisture.
Alameda County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Alameda County
How your county's soil matches Bok Choy's growing requirements.
Soil pH
Your soil pH (6.3–7.7) overlaps with Bok Choy's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Alameda County is excellent for Bok Choy — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Bok Choy.
How to Plant Bok Choy
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Bok Choy
Sow every 4.6 weeks. Last sowing by Oct 13 to harvest before frost.
For a dedicated fall crop, sow by Oct 17.
Plant Water Budget
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 | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Feb | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Mar | 3" | 2.6" | 0.4" | 💧 Light watering |
| Apr | 3" | 1.2" | 1.8" | 🚿 Regular watering |
| May | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Jun | 3" | 0.1" | 2.9" | 🚿 Regular watering |
| Jul | 3" | 0" | 3" | 🚿 Regular watering |
| Aug | 3" | 0" | 3" | 🚿 Regular watering |
| Sep | 3" | 0.2" | 2.8" | 🚿 Regular watering |
| Oct | 3" | 0.6" | 2.4" | 🚿 Regular watering |
| Nov | 3" | 1.5" | 1.5" | 🚿 Regular watering |
| Dec | 3" | 3.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Jan–Dec in Alameda 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 Planting Timeline — Alameda County, CA
Bok Choy Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 21 | Dec 21 – Jan 4 |
| Transplant Outdoors | January 18 | Jan 18 – Feb 1 |
| Direct Sow | December 28 | Dec 28 – Jan 18 |
| Harvest | March 1 | Mar 1 – Apr 5 |
| Fall Sowing | October 17 | Oct 17 – Oct 31 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Transplant Outdoors |
| March | Harvest |
| April | Harvest |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | Start Indoors Direct Sow |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · 1-2 times/week
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 10a
📆 Growing Season
328 days in Alameda County
Growing Tips for Bok Choy in Alameda County
Direct sow Bok Choy outdoors after January 18 in Alameda County when soil has warmed and frost danger has passed.
With summer highs reaching 97°F in Alameda County, provide afternoon shade for Bok Choy and water deeply in the morning.
Your generous 329.0-day season in Alameda 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
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Check more plant combinations with our Companion Planting Checker →
Bok Choy in Other Locations
Frequently Asked Questions
When should I plant Bok Choy in Alameda County, CA?
Alameda County is in Zone 10a with an average last frost of January 18. Plan your Bok Choy planting based on this frost date — see the calendar above for exact timing.
What planting zone is Alameda County, CA?
Alameda County, California is in USDA Hardiness Zone 10a. The average last spring frost is January 18 and first fall frost is December 12.
Your Alameda County Garden Planner — Free
A 24-page printable planner built for Alameda County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.