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When to Plant Brussels Sprouts in Carroll County, MD

Carroll County, Maryland Zone 7a May

What to do in May

Your garden in Carroll County, Maryland is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 17
Avg. first frost October 26
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Start brussels sprouts under lights

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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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.

Carroll County, Maryland is in USDA Zone 7a. The average last spring frost is April 17 and the first fall frost is October 26, giving you a growing season of approximately 192 days.

At an elevation of 715 feet, Carroll County receives approximately 42.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Brussels Sprouts during the growing season.

Carroll County, MD (Zone 7a) Moderate season
192 days
Last Spring Frost April 17
192 growing days
First Fall Frost October 26
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Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Sep 7
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jul 17 – Sep 11
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Aug 8 – Oct 3

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 Carroll County

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

Soil pH

Your soil pH (5.6–6.5) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Carroll 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

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 3.2" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.3" 0" ❄️ Dormant
Apr 3.9" 3.9" 0" ✅ Rainfall sufficient
May 3.9" 3.8" 0.1" 💧 Light watering
Jun 3.9" 3.7" 0.2" 💧 Light watering
Jul 3.9" 4.6" 0" ✅ Rainfall sufficient
Aug 3.9" 3.5" 0.4" 💧 Light watering
Sep 3.9" 3.2" 0.7" 💧 Light watering
Oct 3.9" 3.3" 0.6" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Carroll 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 ~1,678 GDD — county provides 2,928 GDD Excellent fit

Brussels Sprouts Planting Timeline — Carroll County, MD

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 3 Apr 3 – Apr 24
Harvest July 17 Jul 17 – Sep 11
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 Transplant Outdoors
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 · Natural rainfall sufficient

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

192 days in Carroll County

Growing Tips for Brussels Sprouts in Carroll County

Direct sow Brussels Sprouts outdoors after April 17 in Carroll 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 Carroll County, MD?

Carroll County is in Zone 7a with an average last frost of April 17. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carroll County, MD?

Carroll County, Maryland is in USDA Hardiness Zone 7a. The average last spring frost is April 17 and first fall frost is October 26.

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Your Carroll County Garden Planner — Free

A 24-page printable planner built for Carroll 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 Carroll County, MD. 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.