Blog

When to Plant Brussels Sprouts in Grand County, UT

Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.

Grand County, Utah is in USDA Zone 6a. The average last spring frost is April 19 and the first fall frost is October 13, giving you a growing season of approximately 177 days.

At an elevation of 5,415 feet, Grand County receives approximately 23.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91ยฐF, providing good warmth for Brussels Sprouts during the growing season.

Grand County, UT (Zone 6a) Moderate season
177 days
Last Spring Frost April 19
177 growing days
First Fall Frost October 13

Grand County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Sep 7
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jul 19 – Sep 13
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Aug 6 – Oct 1

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 Grand County

How your county's soil matches Brussels Sprouts's growing requirements.

Soil pH

Your soil pH (6.4โ€“7.9) overlaps with Brussels Sprouts's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Grand County is excellent for Brussels Sprouts โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Brussels Sprouts.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Brussels Sprouts.

How to Plant Brussels Sprouts

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

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

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.6″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,176 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Brussels Sprouts

Brussels Sprouts needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Brussels Sprouts Needs Rainfall You Supplement Action
Jan โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 2.2" 0" โ„๏ธ Dormant
Apr 3.9" 2.2" 1.7" ๐Ÿ’ง Light watering
May 3.9" 2.9" 1" ๐Ÿ’ง Light watering
Jun 3.9" 1.5" 2.4" ๐Ÿšฟ Regular watering
Jul 3.9" 2.4" 1.5" ๐Ÿ’ง Light watering
Aug 3.9" 2.1" 1.8" ๐Ÿ’ง Light watering
Sep 3.9" 1.8" 2.1" ๐Ÿšฟ Regular watering
Oct 3.9" 2.1" 1.8" ๐Ÿ’ง Light watering
Nov โ€” 1.6" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Grand County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Brussels Sprouts 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.

Brussels Sprouts needs ~2,008 GDD — county provides 3,230 GDD Excellent fit

Brussels Sprouts Planting Timeline โ€” Grand County, UT

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors April 19 Apr 19 โ€“ May 3
Direct Sow April 5 Apr 5 โ€“ Apr 26
Harvest July 19 Jul 19 โ€“ Sep 13
Fall Sowing August 4 Aug 4 โ€“ Aug 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors
June โ€”
July 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

0.9"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

90โ€“130 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

177 days in Grand County

Growing Tips for Brussels Sprouts in Grand County

Direct sow Brussels Sprouts outdoors after April 19 in Grand County when soil has warmed and frost danger has passed.

Summer highs in Grand County reach 91ยฐF โ€” grow Brussels Sprouts as a spring or fall crop. Use shade cloth if planting in summer.

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

Grand County receives only 23" of rain annually. Brussels Sprouts needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 12-14 weeks before first fall frost. Stake tall plants to prevent toppling. Remove lower leaves as sprouts develop to improve air circulation.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Brussels Sprouts in Grand County, UT?

Grand County is in Zone 6a with an average last frost of April 19. Plan your Brussels Sprouts planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grand County, UT?

Grand County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is April 19 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grand 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 Grand County, UT. Local conditions may vary. Last updated: April 2026.