When to Plant Bok Choy in Maricopa County, AZ
Your May planting checklist for Maricopa County, Arizona
Your garden in Maricopa County, Arizona is working on a schedule, even when you're not. Here's where you should be this May.
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.
Maricopa County, Arizona is in USDA Zone 9b. The average last spring frost is January 31 and the first fall frost is December 6, giving you a growing season of approximately 309 days.
At an elevation of 4,014 feet, Maricopa County receives approximately 12.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 108°F, so Bok Choy may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Bok Choy will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Bok Choy successfully. Mulch heavily to conserve soil moisture.
Maricopa County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.2-8.5
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 Maricopa County
How your county's soil matches Bok Choy's growing requirements.
Soil pH
Your soil pH (7.2–8.5) is more alkaline than Bok Choy prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Maricopa County warms quickly in spring but drains fast. Bok Choy will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (0.7%). Add 2-3 inches of compost before planting 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 07 to harvest before frost.
For a dedicated fall crop, sow by Oct 11.
Plant Water Budget
Water stress score is 10/10 — 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" | 0.9" | 2.1" | 🚿 Regular watering |
| Feb | 3" | 0.8" | 2.2" | 🚿 Regular watering |
| Mar | 3" | 0.7" | 2.3" | 🚿 Regular watering |
| Apr | 3" | 0.5" | 2.5" | 🚿 Regular watering |
| May | 3" | 0.3" | 2.7" | 🚿 Regular watering |
| Jun | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Jul | 3" | 2.1" | 0.9" | 💧 Light watering |
| Aug | 3" | 2.3" | 0.7" | 💧 Light watering |
| Sep | 3" | 1.9" | 1.1" | 💧 Light watering |
| Oct | 3" | 1.2" | 1.8" | 🚿 Regular watering |
| Nov | 3" | 0.6" | 2.4" | 🚿 Regular watering |
| Dec | 3" | 0.8" | 2.2" | 🚿 Regular watering |
Water needs are for active growing months only (Jan–Dec in Maricopa 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 — Maricopa County, AZ
Bok Choy Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 3 | Jan 3 – Jan 17 |
| Transplant Outdoors | January 31 | Jan 31 – Feb 14 |
| Direct Sow | January 10 | Jan 10 – Jan 31 |
| Harvest | March 14 | Mar 14 – Apr 18 |
| Fall Sowing | October 11 | Oct 11 – Oct 25 |
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 | — |
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: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
309 days in Maricopa County
Growing Tips for Bok Choy in Maricopa County
Direct sow Bok Choy outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.
Sandy soil in Maricopa County dries quickly — mulch Bok Choy with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 108°F in Maricopa County, provide afternoon shade for Bok Choy and water deeply in the morning.
Your generous 310.0-day season in Maricopa 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 Maricopa County, AZ?
Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Bok Choy planting based on this frost date — see the calendar above for exact timing.
What planting zone is Maricopa County, AZ?
Maricopa County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is January 31 and first fall frost is December 6.
Your Maricopa County Garden Planner — Free
A 24-page printable planner built for Maricopa 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.