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When to Plant Pac Choi in Caribou County, ID

Caribou County, Idaho Zone 5a May

What to do in May

Each item below is timed to Caribou County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 30
Avg. first frost September 16
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Harden off and plant pac choi

    Your last frost (May 30) has passed. These warm-season crops can handle outdoor soil now.

  2. Sow pac choi where they'll grow

    Your soil is 34°F — warm enough for these to germinate without babying.

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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.

Caribou County, Idaho is in USDA Zone 5a. The average last spring frost is May 30 and the first fall frost is September 16, giving you a growing season of approximately 109 days.

At an elevation of 6,562 feet, Caribou County receives approximately 15.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Pac Choi to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Pac Choi successfully. Mulch heavily to conserve soil moisture.

Caribou County, ID (Zone 5a) Short season
109 days
Last Spring Frost May 30
109 growing days
First Fall Frost September 16

Caribou County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Jun 29 – Jul 27
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 11 – Aug 8
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: May 13 Transplant: Jun 17 🍅 Harvest: Jul 29 – Aug 26

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 Caribou County

How your county's soil matches Pac Choi's growing requirements.

Soil pH

Your soil pH (6.8–8.1) overlaps with Pac Choi's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Caribou County is excellent for Pac Choi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Pac Choi.

How to Plant Pac Choi

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Pac Choi

3
successive plantings in your 109-day season

Sow every 4.6 weeks. Last sowing by Jul 23 to harvest before frost.

For a dedicated fall crop, sow by Jul 08.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,060 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.2" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 6.5" 1.6" 4.9" 🚿 Regular watering
Jun 6.5" 1" 5.5" 🚿 Regular watering
Jul 6.5" 1.5" 5" 🚿 Regular watering
Aug 6.5" 1.4" 5.1" 🚿 Regular watering
Sep 6.5" 1.2" 5.3" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Caribou 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 needs ~511 GDD — county provides 1,171 GDD Excellent fit

Pac Choi Planting Timeline — Caribou County, ID

Pac Choi Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 16 May 16 – Jun 6
Harvest July 11 Jul 11 – Aug 8
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing Harvest
August Harvest
September
October
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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

109 days in Caribou County

Growing Tips for Pac Choi in Caribou County

Direct sow Pac Choi outdoors after May 30 in Caribou County when soil has warmed and frost danger has passed.

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.

Caribou County receives only 15" of rain annually. Pac Choi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pac Choi in Caribou County, ID?

Caribou County is in Zone 5a with an average last frost of May 30. Plan your Pac Choi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Caribou County, ID?

Caribou County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 30 and first fall frost is September 16.

🌱

Your Caribou County Garden Planner — Free

A 24-page printable planner built for Caribou County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Caribou County, ID. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.