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When to Plant Pac Choi in Polk County, IA

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.

Polk County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,037 feet, Polk County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Pac Choi during the growing season.

Polk County, IA (Zone 5a) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 3 – Jul 1
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 13 – Jul 11
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 23 – Jul 21

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 1,936 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Pac Choi needs ~689 GDD — county provides 2,291 GDD Excellent fit

Pac Choi Planting Timeline โ€” Polk County, IA

Pac Choi Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing July 29 Jul 29 โ€“ Aug 12
Harvest June 13 Jun 13 โ€“ Jul 11

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

40โ€“55 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

158 days

Growing Tips for Polk County

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

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Pac Choi in Polk County, IA?

Polk County is in Zone 5a with an average last frost of May 2. Plan your Pac Choi planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Polk County, IA?

Polk County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Polk County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Polk County, IA. Local conditions may vary. Last updated: April 2026.