When to Plant Pac Choi in Mercer County, MO
Your May gardening checklist
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
-
Start pac choi indoors
Label every cell. You will absolutely forget which is which otherwise.
June will be here before you know it — start on
- First harvests: pac choi
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.
Mercer County, Missouri is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.
At an elevation of 523 feet, Mercer County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Pac Choi during the growing season.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.8
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 Mercer County
How your county's soil matches Pac Choi's growing requirements.
Soil pH
Your soil pH (5.6–6.8) overlaps with Pac Choi's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Mercer County is excellent for Pac Choi — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Pac Choi.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Pac Choi.
How to Plant Pac Choi
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Pac Choi
Sow every 4.6 weeks. Last sowing by Aug 20 to harvest before frost.
For a dedicated fall crop, sow by Aug 05.
Plant Water Budget
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 6.5" | 4.3" | 2.2" | 💧 Light watering |
| May | 6.5" | 4.8" | 1.7" | 💧 Light watering |
| Jun | 6.5" | 5.1" | 1.4" | 💧 Light watering |
| Jul | 6.5" | 4" | 2.5" | 💧 Light watering |
| Aug | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Sep | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Oct | 6.5" | 3.2" | 3.3" | 🚿 Regular watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Mercer 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 — Mercer County, MO
Pac Choi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 1 | Jun 1 – Jun 29 |
| Fall Sowing | August 5 | Aug 5 – Aug 19 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Harvest |
| July | — |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · Only during dry spells
📅 Days to Maturity
40–55 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
177 days in Mercer County
Growing Tips for Pac Choi in Mercer County
Direct sow Pac Choi outdoors after April 20 in Mercer County when soil has warmed and frost danger has passed.
Your generous 177.0-day season in Mercer 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
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Pac Choi in Other Locations
Frequently Asked Questions
When should I plant Pac Choi in Mercer County, MO?
Mercer County is in Zone 5b with an average last frost of April 20. Plan your Pac Choi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, MO?
Mercer County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 14.
Your Mercer County Garden Planner — Free
A 24-page printable planner built for Mercer County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.