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When to Plant Bok Choy in Box Elder County, UT

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.

Box Elder County, Utah is in USDA Zone 6a. The average last spring frost is May 22 and the first fall frost is October 3, giving you a growing season of approximately 134 days.

At an elevation of 4,039 feet, Box Elder County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Bok Choy during the growing season.

Box Elder County, UT (Zone 6a) Short season
134 days
Last Spring Frost May 22
134 growing days
First Fall Frost October 3

Box Elder County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 23 – Jul 28
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: Jul 3 – Aug 7
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Jul 22 – 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 Box Elder County

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

Soil pH

Your soil pH (6.3โ€“7.9) overlaps with Bok Choy's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Box Elder County is excellent for Bok Choy โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). 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

3
successive plantings in your 134-day season

Sow every 4.6 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 25.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” 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 โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 2.7" 0" โ„๏ธ Dormant
May 3" 2.4" 0.6" ๐Ÿ’ง Light watering
Jun 3" 1.7" 1.3" ๐Ÿ’ง Light watering
Jul 3" 2.4" 0.6" ๐Ÿ’ง Light watering
Aug 3" 2.8" 0.2" ๐Ÿ’ง Light watering
Sep 3" 1.8" 1.2" ๐Ÿ’ง Light watering
Oct 3" 2.4" 0.6" ๐Ÿ’ง Light watering
Nov โ€” 1.7" 0" โ„๏ธ Dormant
Dec โ€” 1.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Box Elder County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~762 GDD — county provides 2,043 GDD Excellent fit

Bok Choy Planting Timeline โ€” Box Elder County, UT

Bok Choy Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 โ€“ May 1
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 8 May 8 โ€“ May 29
Harvest July 3 Jul 3 โ€“ Aug 7
Fall Sowing July 25 Jul 25 โ€“ Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

134 days in Box Elder County

Growing Tips for Bok Choy in Box Elder County

Direct sow Bok Choy outdoors after May 22 in Box Elder 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 Box Elder County, UT?

Box Elder County is in Zone 6a with an average last frost of May 22. Plan your Bok Choy planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Box Elder County, UT?

Box Elder County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 22 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Box Elder County gardeners in Zone 6a 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 Box Elder County, UT. Local conditions may vary. Last updated: April 2026.