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When to Plant Brussels Sprouts in Nelson County, ND

Nelson County, North Dakota Zone 4a May

May to-do list for Nelson County, North Dakota

Your Nelson County, North Dakota 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 12
Avg. first frost September 27
Soil temp (4") 49°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Get brussels sprouts in the ground

    Frost risk is low now in Nelson County, North Dakota. If you've been covering beds overnight, you can stop.

  2. Seed brussels sprouts outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Looking ahead to 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.

Nelson County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 27, giving you a growing season of approximately 138 days.

At an elevation of 547 feet, Nelson County receives approximately 33.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Brussels Sprouts to ensure they mature before fall.

Nelson County, ND (Zone 4a) Short season
138 days
Last Spring Frost May 12
138 growing days
First Fall Frost September 27

Nelson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Aug 7 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Aug 11 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 11 Transplant: May 23 🍅 Harvest: Aug 22 – Oct 17

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 Nelson County

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

Soil pH

Your soil pH (6.6–7.8) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Brussels Sprouts will thrive.

How to Plant Brussels Sprouts

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 3.9" 4.6" 0" ✅ Rainfall sufficient
Jun 3.9" 5.8" 0" ✅ Rainfall sufficient
Jul 3.9" 3.9" 0" ✅ Rainfall sufficient
Aug 3.9" 4.1" 0" ✅ Rainfall sufficient
Sep 3.9" 3.5" 0.4" 💧 Light watering
Oct 2" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Nelson 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 ~1,100 GDD — county provides 1,380 GDD Good fit

Brussels Sprouts Planting Timeline — Nelson County, ND

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 5 May 5 – May 26
Harvest August 11 Aug 11 – Oct 6
Fall Sowing July 5 Jul 5 – Jul 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

138 days in Nelson County

Growing Tips for Brussels Sprouts in Nelson County

Direct sow Brussels Sprouts outdoors after May 12 in Nelson County when soil has warmed and frost danger has passed.

Your 138.0-day growing season in Nelson 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.

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 Nelson County, ND?

Nelson County is in Zone 4a with an average last frost of May 12. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nelson County, ND?

Nelson County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 27.

🌱

Your Nelson County Garden Planner — Free

A 24-page printable planner built for Nelson County (Zone 4a). 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 Nelson County, ND. 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.