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When to Plant Brussels Sprouts in Assumption Parish, LA

Assumption Parish, Louisiana Zone 9b May

Your May game plan for Assumption Parish, Louisiana

We've pulled the most time-sensitive tasks for Assumption Parish, Louisiana this May and put them front and centre. Tackle them in order.

Avg. last frost February 13
Avg. first frost December 5
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Start harvesting brussels sprouts

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before June arrives, get these ready
  • First harvests: 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.

Assumption Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 13 and the first fall frost is December 5, giving you a growing season of approximately 295 days.

At an elevation of 126 feet, Assumption Parish receives approximately 55.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 104°F, so Brussels Sprouts may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Brussels Sprouts will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Brussels Sprouts root diseases.

Assumption Parish, LA (Zone 9b) Year-round
295 days
Last Spring Frost February 13
295 growing days
First Fall Frost December 5

Assumption Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Start indoors: Jan 7 Transplant: Feb 4 🍅 Harvest: May 6 – Jul 1
Recommended (50%) ✓ Fits season (148 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: May 15 – Jul 10
Safe Start (90%) ✓ Fits season (139 days to spare)
Start indoors: Feb 9 Transplant: Mar 9 🍅 Harvest: Jun 8 – Aug 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 Assumption Parish

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

Soil pH

Your soil pH (5.0–6.3) is more acidic than Brussels Sprouts prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Assumption Parish 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 moderate (2.2%). Annual compost additions will help Brussels Sprouts.

How to Plant Brussels Sprouts

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.8″/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 4.4" 0" ❄️ Dormant
Feb 3.9" 4.6" 0" ✅ Rainfall sufficient
Mar 3.9" 5.5" 0" ✅ Rainfall sufficient
Apr 3.9" 4.3" 0" ✅ Rainfall sufficient
May 3.9" 4.4" 0" ✅ Rainfall sufficient
Jun 3.9" 4.8" 0" ✅ Rainfall sufficient
Jul 3.9" 6.2" 0" ✅ Rainfall sufficient
Aug 3.9" 5" 0" ✅ Rainfall sufficient
Sep 3.9" 3.9" 0" ✅ Rainfall sufficient
Oct 3.9" 3.8" 0.1" 💧 Light watering
Nov 3.9" 4.2" 0" ✅ Rainfall sufficient
Dec 3.9" 4.6" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Assumption Parish). 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 ~3,080 GDD — county provides 8,288 GDD Excellent fit

Brussels Sprouts Planting Timeline — Assumption Parish, LA

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow January 23 Jan 23 – Feb 13
Harvest May 15 May 15 – Jul 10
Fall Sowing October 10 Oct 10 – Oct 24

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9b

📆 Growing Season

295 days in Assumption Parish

Growing Tips for Brussels Sprouts in Assumption Parish

Direct sow Brussels Sprouts outdoors after February 13 in Assumption Parish when soil has warmed and frost danger has passed.

Sandy soil in Assumption Parish dries quickly — mulch Brussels Sprouts with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Summer highs in Assumption Parish reach 104°F — grow Brussels Sprouts as a spring or fall crop. Use shade cloth if planting in summer.

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 Assumption Parish, LA?

Assumption Parish is in Zone 9b with an average last frost of February 13. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Assumption Parish, LA?

Assumption Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 13 and first fall frost is December 5.

🌱

Your Assumption Parish Garden Planner — Free

A 24-page printable planner built for Assumption Parish (Zone 9b). 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 Assumption Parish, LA. 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.