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When to Plant Brussels Sprouts in Colfax County, NM

Colfax County, New Mexico Zone 6a May

Your May planting checklist for Colfax County, New Mexico

Your Colfax County, New Mexico garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 15
Avg. first frost September 26
Soil temp (4") 47°F
Watering Critical
Pest pressure Low
Daylight 14 hrs
  1. Time to transplant brussels sprouts

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Sow brussels sprouts where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

A few tasks this May that'll pay off in June
  • 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.

Colfax County, New Mexico is in USDA Zone 6a. The average last spring frost is May 15 and the first fall frost is September 26, giving you a growing season of approximately 134 days.

At an elevation of 5,131 feet, Colfax County receives approximately 15.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 84°F, so choose short-season varieties of Brussels Sprouts to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Brussels Sprouts will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Brussels Sprouts successfully. Mulch heavily to conserve soil moisture.

Colfax County, NM (Zone 6a) Short season
134 days
Last Spring Frost May 15
134 growing days
First Fall Frost September 26

Colfax County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.1-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Sep 15 – Nov 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 Colfax County

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

Soil pH

Your soil pH (7.1–8.1) is more alkaline than Brussels Sprouts prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Colfax County warms quickly in spring but drains fast. Brussels Sprouts will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Brussels Sprouts.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting 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
0.5″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 979 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.9" 0" ❄️ Dormant
Apr 0.5" 0" ❄️ Dormant
May 3.9" 0.4" 3.5" 🚿 Regular watering
Jun 3.9" 0.5" 3.4" 🚿 Regular watering
Jul 3.9" 3" 0.9" 💧 Light watering
Aug 3.9" 2.9" 1" 💧 Light watering
Sep 3.9" 2" 1.9" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Colfax 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 ~1,430 GDD — county provides 1,742 GDD Good fit

Brussels Sprouts Planting Timeline — Colfax County, NM

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 1 May 1 – May 22
Harvest August 14 Aug 14 – Oct 9
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
May Transplant Outdoors Direct Sow
June
July Fall Sowing
August Fall Sowing Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 2-3 times/week

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

134 days in Colfax County

Growing Tips for Brussels Sprouts in Colfax County

Direct sow Brussels Sprouts outdoors after May 15 in Colfax County when soil has warmed and frost danger has passed.

Sandy soil in Colfax County dries quickly — mulch Brussels Sprouts with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your 134.0-day growing season in Colfax County is tight for Brussels Sprouts (90.0-130.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Colfax County receives only 16" 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 Colfax County, NM?

Colfax County is in Zone 6a with an average last frost of May 15. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colfax County, NM?

Colfax County, New Mexico is in USDA Hardiness Zone 6a. The average last spring frost is May 15 and first fall frost is September 26.

🌱

Your Colfax County Garden Planner — Free

A 24-page printable planner built for Colfax County (Zone 6a). 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 Colfax County, NM. 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.