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When to Plant Brussels Sprouts in Sierra County, NM

Sierra County, New Mexico Zone 7a April

What to do in April

Here's what deserves your attention in Sierra County, New Mexico this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 15
Avg. first frost October 26
Soil temp (4") 44°F
Watering Critical
Pest pressure Moderate
Daylight 12.8 hrs
  1. Move brussels sprouts into the garden

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Plant brussels sprouts from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

Before May arrives, get these ready
  • 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.

Sierra County, New Mexico is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 26, giving you a growing season of approximately 194 days.

At an elevation of 4,898 feet, Sierra County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 88°F, providing good warmth for Brussels Sprouts during the growing season. 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.

Sierra County, NM (Zone 7a) Moderate season
194 days
Last Spring Frost April 15
194 growing days
First Fall Frost October 26
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Sierra County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Feb 23 Transplant: Mar 30 🍅 Harvest: Jun 29 – Aug 24
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 9
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Aug 3 – Sep 28

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 Sierra County

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

Soil pH

Your soil pH (7.3–8.5) is more alkaline than Brussels Sprouts prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Sierra 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 (0.7%). 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
0.4″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,644 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 3.9" 0.6" 3.3" 🚿 Regular watering
May 3.9" 0.4" 3.5" 🚿 Regular watering
Jun 3.9" 0.5" 3.4" 🚿 Regular watering
Jul 3.9" 2.7" 1.2" 💧 Light watering
Aug 3.9" 3.3" 0.6" 💧 Light watering
Sep 3.9" 2.3" 1.6" 💧 Light watering
Oct 3.9" 1.7" 2.2" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sierra 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 ~1,760 GDD — county provides 3,104 GDD Excellent fit

Brussels Sprouts Planting Timeline — Sierra County, NM

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest July 15 Jul 15 – Sep 9
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Fall Sowing Harvest
September Harvest
October
November
December
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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 7a

📆 Growing Season

194 days in Sierra County

Growing Tips for Brussels Sprouts in Sierra County

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

Sandy soil in Sierra 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.

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.

Sierra County receives only 17" 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 Sierra County, NM?

Sierra County is in Zone 7a with an average last frost of April 15. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sierra County, NM?

Sierra County, New Mexico is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 26.

🌱

Your Sierra County Garden Planner — Free

A 24-page printable planner built for Sierra 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 Sierra County, NM. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.