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When to Plant Brussels Sprouts in Hardin County, TN

Hardin County, Tennessee Zone 7b May

May to-do list for Hardin County, Tennessee

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 31
Avg. first frost October 28
Soil temp (4") 62°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Start brussels sprouts under lights

    Your window is short. These crops want several weeks of indoor growth before they go outside.

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.

Hardin County, Tennessee is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is October 28, giving you a growing season of approximately 211 days.

At an elevation of 3,095 feet, Hardin County receives approximately 53.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Brussels Sprouts during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Brussels Sprouts root diseases.

Hardin County, TN (Zone 7b) Long season
211 days
Last Spring Frost March 31
211 growing days
First Fall Frost October 28

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (67 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Jun 23 – Aug 18
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Jun 30 – Aug 25
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 16 – Sep 10

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 Hardin County

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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
1.1″/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 4.2" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.9" 5.2" 0" ✅ Rainfall sufficient
Apr 3.9" 3.7" 0.2" 💧 Light watering
May 3.9" 4.7" 0" ✅ Rainfall sufficient
Jun 3.9" 4.8" 0" ✅ Rainfall sufficient
Jul 3.9" 6" 0" ✅ Rainfall sufficient
Aug 3.9" 4.9" 0" ✅ Rainfall sufficient
Sep 3.9" 3.5" 0.4" 💧 Light watering
Oct 3.9" 3.9" 0" ✅ Rainfall sufficient
Nov 4.3" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Hardin 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 ~2,172 GDD — county provides 4,167 GDD Excellent fit

Brussels Sprouts Planting Timeline — Hardin County, TN

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow March 17 Mar 17 – Apr 7
Harvest June 30 Jun 30 – Aug 25
Fall Sowing August 19 Aug 19 – Sep 2

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August Fall Sowing Harvest
September Fall Sowing
October
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 7b

📆 Growing Season

211 days in Hardin County

Growing Tips for Brussels Sprouts in Hardin County

Direct sow Brussels Sprouts outdoors after March 31 in Hardin County when soil has warmed and frost danger has passed.

Summer highs in Hardin County reach 93°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 Hardin County, TN?

Hardin County is in Zone 7b with an average last frost of March 31. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, TN?

Hardin County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is October 28.

🌱

Your Hardin County Garden Planner — Free

A 24-page printable planner built for Hardin County (Zone 7b). 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 Hardin County, TN. 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.