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When to Plant Brussels Sprouts in Mesa County, CO

Mesa County, Colorado Zone 7a May

This month in Mesa County, Colorado

May is a pivotal month for Mesa County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 1
Avg. first frost October 9
Soil temp (4") 45°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
  1. Transplant brussels sprouts outside

    Your last frost (May 1) has passed. These warm-season crops can handle outdoor soil now.

Coming up in June — start thinking about
  • Starting indoors: brussels sprouts

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

Mesa County, Colorado is in USDA Zone 7a. The average last spring frost is May 1 and the first fall frost is October 9, giving you a growing season of approximately 161 days.

At an elevation of 6,091 feet, Mesa County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Brussels Sprouts during the growing season.

Mesa County, CO (Zone 7a) Moderate season
161 days
Last Spring Frost May 1
161 growing days
First Fall Frost October 9

Mesa County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 16
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 25
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 8

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 Mesa County

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

Soil pH

Your soil pH (6.7–8.1) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Mesa County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). 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
0.4″/week
Watering frequency 1-2 times/week
Season total 502 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 3.9" 2.6" 1.3" 💧 Light watering
Jun 3.9" 1.8" 2.1" 🚿 Regular watering
Jul 3.9" 2.1" 1.8" 💧 Light watering
Aug 3.9" 2.5" 1.4" 💧 Light watering
Sep 3.9" 1.9" 2" 🚿 Regular watering
Oct 3.9" 1.8" 2.1" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mesa County). Supplement amounts are based on average rainfall — 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" — 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.

Brussels Sprouts needs ~2,008 GDD — county provides 2,938 GDD Excellent fit

Brussels Sprouts Planting Timeline — Mesa County, CO

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 17 Apr 17 – May 8
Harvest July 31 Jul 31 – Sep 25
Fall Sowing July 31 Jul 31 – Aug 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

161 days in Mesa County

Growing Tips for Brussels Sprouts in Mesa County

Direct sow Brussels Sprouts outdoors after May 01 in Mesa County when soil has warmed and frost danger has passed.

Summer highs in Mesa County reach 91°F — 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.

Mesa County receives only 23" of rain annually. Brussels Sprouts needs consistent moisture — 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 Mesa County, CO?

Mesa County is in Zone 7a with an average last frost of May 1. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mesa County, CO?

Mesa County, Colorado is in USDA Hardiness Zone 7a. The average last spring frost is May 1 and first fall frost is October 9.

🌱

Your Mesa County Garden Planner — Free

A 24-page printable planner built for Mesa County (Zone 7a). 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 Mesa County, CO. 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.