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When to Plant Bok Choy in Platte County, WY

Platte County, Wyoming Zone 5a May

Top priorities for Platte County, Wyoming gardeners in May

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 13
Avg. first frost September 26
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Move bok choy from tray to bed

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

Coming up in June — start thinking about
  • Starting indoors: bok choy
  • First harvests: bok choy

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Bok choy is a Chinese cabbage variety with crisp white stalks and dark green leaves. It is a fast-growing cool-season crop ideal for stir-fries and soups.

Platte County, Wyoming is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 26, giving you a growing season of approximately 136 days.

At an elevation of 7,409 feet, Platte County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Bok Choy to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Bok Choy successfully. Mulch heavily to conserve soil moisture.

Platte County, WY (Zone 5a) Short season
136 days
Last Spring Frost May 13
136 growing days
First Fall Frost September 26

Platte County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 22 – Jul 27
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 24 – Jul 29
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Jul 6 – Aug 10

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 Platte County

How your county's soil matches Bok Choy's growing requirements.

Soil pH

Your soil pH (6.5–8.3) overlaps with Bok Choy's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Platte County is excellent for Bok Choy — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Bok Choy.

How to Plant Bok Choy

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 Bok Choy

4
successive plantings in your 136-day season

Sow every 4.6 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 187 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Bok Choy

Bok Choy needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Bok Choy Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3" 2" 1" 💧 Light watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 1.5" 1.5" 🚿 Regular watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 1.3" 1.7" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Platte County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Bok Choy 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.

Bok Choy needs ~612 GDD — county provides 1,666 GDD Excellent fit

Bok Choy Planting Timeline — Platte County, WY

Bok Choy 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 29
Fall Sowing July 18 Jul 18 – Aug 1

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

0.7"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

136 days in Platte County

Growing Tips for Bok Choy in Platte County

Direct sow Bok Choy outdoors after May 13 in Platte County when soil has warmed and frost danger has passed.

Common pests for Bok Choy 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 for best results. Keep soil consistently moist. Harvest whole heads or cut outer leaves for a cut-and-come-again approach.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bok Choy in Platte County, WY?

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

What planting zone is Platte County, WY?

Platte County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is September 26.

🌱

Your Platte County Garden Planner — Free

A 24-page printable planner built for Platte 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.

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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 Platte County, WY. 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.