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When to Plant Brussels Sprouts in Rock County, NE

Rock County, Nebraska Zone 5a May

Top priorities for Rock County, Nebraska gardeners in May

A quick May briefing for Rock County, Nebraska gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 10
Avg. first frost October 6
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Plant out brussels sprouts

    Your last frost (May 10) has passed. These warm-season crops can handle outdoor soil now.

To set up a strong June, finish these tasks
  • 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.

Rock County, Nebraska is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 6, giving you a growing season of approximately 149 days.

At an elevation of 1,012 feet, Rock County receives approximately 32.4 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Brussels Sprouts to ensure they mature before fall.

Rock County, NE (Zone 5a) Short season
149 days
Last Spring Frost May 10
149 growing days
First Fall Frost October 6

Rock County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 25
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Aug 9 – Oct 4
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 16

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 Rock County

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

Soil pH

Your soil pH (6.7–7.3) is within Brussels Sprouts's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). 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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 3.9" 4.6" 0" ✅ Rainfall sufficient
Jun 3.9" 5.6" 0" ✅ Rainfall sufficient
Jul 3.9" 3.5" 0.4" 💧 Light watering
Aug 3.9" 4" 0" ✅ Rainfall sufficient
Sep 3.9" 3.2" 0.7" 💧 Light watering
Oct 3.9" 1.8" 2.1" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Rock 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 ~1,182 GDD — county provides 1,601 GDD Excellent fit

Brussels Sprouts Planting Timeline — Rock County, NE

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest August 9 Aug 9 – Oct 4
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
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 · Natural rainfall sufficient

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

149 days in Rock County

Growing Tips for Brussels Sprouts in Rock County

Direct sow Brussels Sprouts outdoors after May 10 in Rock County when soil has warmed and frost danger has passed.

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 Rock County, NE?

Rock County is in Zone 5a with an average last frost of May 10. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rock County, NE?

Rock County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 6.

🌱

Your Rock County Garden Planner — Free

A 24-page printable planner built for Rock County (Zone 5a). 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 Rock County, NE. 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.