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When to Plant Brussels Sprouts in Somerset County, ME

Somerset County, Maine Zone 5a May

This month in Somerset County, Maine

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 22
Avg. first frost September 26
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Get brussels sprouts in the ground

    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. Seed brussels sprouts outdoors

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

June prep starts now
  • 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.

Somerset County, Maine is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 26, giving you a growing season of approximately 127 days.

At an elevation of 356 feet, Somerset County receives approximately 48.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Brussels Sprouts to ensure they mature before fall.

Somerset County, ME (Zone 5a) Short season
127 days
Last Spring Frost May 22
127 growing days
First Fall Frost September 26
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Somerset County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 9
Recommended (50%) ✗ May not fit
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 16
Safe Start (90%) ✗ May not fit
Start indoors: Apr 29 Transplant: Jun 3 🍅 Harvest: Sep 2 – Oct 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 Somerset County

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

Soil pH

Your soil pH (4.8–6.4) is more acidic than Brussels Sprouts prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Brussels Sprouts.

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
1.6″/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 2.9" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.6" 0" ❄️ Dormant
May 3.9" 4.2" 0" ✅ Rainfall sufficient
Jun 3.9" 5" 0" ✅ Rainfall sufficient
Jul 3.9" 4" 0" ✅ Rainfall sufficient
Aug 3.9" 4.6" 0" ✅ Rainfall sufficient
Sep 3.9" 4" 0" ✅ Rainfall sufficient
Oct 4.2" 0" ❄️ Dormant
Nov 3.8" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Somerset 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 1,270 GDD Good fit

Brussels Sprouts Planting Timeline — Somerset County, ME

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 – May 1
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 8 May 8 – May 29
Harvest August 21 Aug 21 – Oct 16
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 Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors
July Fall Sowing
August Fall Sowing Harvest
September Harvest
October Harvest
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: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

127 days in Somerset County

Growing Tips for Brussels Sprouts in Somerset County

Direct sow Brussels Sprouts outdoors after May 22 in Somerset County when soil has warmed and frost danger has passed.

Your 127.0-day growing season in Somerset 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 Somerset County, ME?

Somerset County is in Zone 5a with an average last frost of May 22. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Somerset County, ME?

Somerset County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 26.

🌱

Your Somerset County Garden Planner — Free

A 24-page printable planner built for Somerset 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 Somerset County, ME. 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.