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When to Plant Collard Greens in Box Elder County, UT

Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

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 Collard Greens 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 (16 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jul 7 – Sep 8
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: Jul 17 – Sep 18
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Aug 5 – Oct 7

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 Collard Greens's growing requirements.

Soil pH

Your soil pH (6.3โ€“7.9) is more alkaline than Collard Greens prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Collard Greens.

How to Plant Collard Greens

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 Collard Greens

2
successive plantings in your 134-day season

Sow every 6.3 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 25.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 46 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens 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 3.5" 2.4" 1.1" ๐Ÿ’ง Light watering
Jun 3.5" 1.7" 1.8" ๐Ÿšฟ Regular watering
Jul 3.5" 2.4" 1.1" ๐Ÿ’ง Light watering
Aug 3.5" 2.8" 0.7" ๐Ÿ’ง Light watering
Sep 3.5" 1.8" 1.7" ๐Ÿ’ง Light watering
Oct 3.5" 2.4" 1.1" 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.

Collard Greens 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.

Collard Greens needs ~991 GDD — county provides 2,043 GDD Excellent fit

Collard Greens Planting Timeline โ€” Box Elder County, UT

Collard Greens 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 17 Jul 17 โ€“ Sep 18
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 Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

55โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

134 days in Box Elder County

Growing Tips for Collard Greens in Box Elder County

Direct sow Collard Greens outdoors after May 22 in Box Elder County when soil has warmed and frost danger has passed.

Common pests for Collard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Box Elder County, UT?

Box Elder County is in Zone 6a with an average last frost of May 22. Plan your Collard Greens 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.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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.