When to Plant Pac Choi in Maricopa County, AZ
May to-do list for Maricopa County, Arizona
Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.
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.
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 Pac Choi may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Pac Choi will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Pac Choi 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 Pac Choi's growing requirements.
Soil pH
Your soil pH (7.2–8.5) is more alkaline than Pac Choi 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. Pac Choi 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 Pac Choi.
How to Plant Pac Choi
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Pac Choi
Sow every 4.6 weeks. Last sowing by Oct 12 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 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 | 6.5" | 0.9" | 5.6" | 🚿 Regular watering |
| Feb | 6.5" | 0.8" | 5.7" | 🚿 Regular watering |
| Mar | 6.5" | 0.7" | 5.8" | 🚿 Regular watering |
| Apr | 6.5" | 0.5" | 6" | 🚿 Regular watering |
| May | 6.5" | 0.3" | 6.2" | 🚿 Regular watering |
| Jun | 6.5" | 0.4" | 6.1" | 🚿 Regular watering |
| Jul | 6.5" | 2.1" | 4.4" | 🚿 Regular watering |
| Aug | 6.5" | 2.3" | 4.2" | 🚿 Regular watering |
| Sep | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Oct | 6.5" | 1.2" | 5.3" | 🚿 Regular watering |
| Nov | 6.5" | 0.6" | 5.9" | 🚿 Regular watering |
| Dec | 6.5" | 0.8" | 5.7" | 🚿 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.
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 Planting Timeline — Maricopa County, AZ
Pac Choi 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 11 |
| 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
1.5"/week · 2-3 times/week
📅 Days to Maturity
40–55 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 Pac Choi in Maricopa County
Direct sow Pac Choi outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.
Sandy soil in Maricopa County dries quickly — mulch Pac Choi 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 Pac Choi and water deeply in the morning.
Your generous 310.0-day season in Maricopa 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.
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
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Pac Choi in Other Locations
Frequently Asked Questions
When should I plant Pac Choi in Maricopa County, AZ?
Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Pac Choi 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.