Blog

When to plant Pac Choi in Big Horn County County,

For Pac Choi in Big Horn County County, the safe spring window opens around April 29 and closes around May 20. Last expected frost is May 13, first fall frost September 30, giving a 140-day growing season. A second sowing from July 22 to August 5 extends the harvest into fall.

When to Plant Pac Choi in Big Horn County, MT

Big Horn County, Montana Zone 5a June

Big Horn County, Montana gardeners: here's your June plan

A quick June briefing for Big Horn County, Montana gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 13
Avg. first frost September 30
Soil temp (4") 49°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Sow pac choi in trays indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Bring in the pac choi

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

A few tasks this June that'll pay off in July
  • First harvests: pac choi
  • Fall sowing: pac choi

Instant PDF download. No spam, unsubscribe any time.

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.

Big Horn County, Montana is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 5,955 feet, Big Horn County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Pac Choi to ensure they mature before fall.

Big Horn County, MT (Zone 5a) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Big Horn County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Pac Choi Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jun 19 – Jul 17
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 24 – Jul 22
Safe Start (90%) ✓ Fits season (67 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Jul 12 – Aug 9

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 Big Horn County

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

Soil pH

Your soil pH (6.2–7.6) overlaps with Pac Choi's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). 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

4
successive plantings in your 140-day season

Sow every 4.6 weeks. Last sowing by Aug 06 to harvest before frost.

For a dedicated fall crop, sow by Jul 22.

Pac Choi Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,234 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 6.5" 2.9" 3.6" 🚿 Regular watering
Jun 6.5" 1.7" 4.8" 🚿 Regular watering
Jul 6.5" 2.2" 4.3" 🚿 Regular watering
Aug 6.5" 2" 4.5" 🚿 Regular watering
Sep 6.5" 1.8" 4.7" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Big Horn 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 ~582 GDD — county provides 1,715 GDD Excellent fit

Pac Choi Planting Timeline — Big Horn County, MT

Pac Choi Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 13 May 13 – May 27
Direct Sow April 29 Apr 29 – May 20
Harvest June 24 Jun 24 – Jul 22
Fall Sowing July 22 Jul 22 – Aug 5

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

Month-by-Month Timeline

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

140 days in Big Horn County

Growing Tips for Pac Choi in Big Horn County

Direct sow Pac Choi outdoors after May 13 in Big Horn County when soil has warmed and frost danger has passed.

Your generous 140.0-day season in Big Horn 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.

Big Horn County receives only 22" 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 Big Horn County, MT?

Big Horn County is in Zone 5a with an average last frost of May 13. Plan your Pac Choi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Big Horn County, MT?

Big Horn County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is September 30.

When should I plant Pac Choi in Big Horn County County, ?

In Big Horn County County, , plant Pac Choi after the last frost (around May 13) and before the first frost (around September 30). Best results when soil holds above 50°F.

What growing zone is Big Horn County County, for Pac Choi?

Big Horn County County sits in USDA Zone 5a. Pac Choi grows reliably in zones 2a through 11b, so it's a good fit here.

Can Pac Choi grow in Big Horn County County's climate?

Yes — Pac Choi grows well in Big Horn County County's temperate climate. Big Horn County County averages a 140-day frost-free season, with last frost around May 13 and first frost around September 30.

🌱

Your Big Horn County Garden Planner — Free

A 22-page printable planner built for Big Horn 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 Big Horn County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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