When to Plant Brussels Sprouts in Roane County, TN
May in the garden — Roane County, Tennessee
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.
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Start brussels sprouts under lights
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.
Roane County, Tennessee is in USDA Zone 7b. The average last spring frost is April 9 and the first fall frost is October 28, giving you a growing season of approximately 202 days.
At an elevation of 3,597 feet, Roane County receives approximately 54.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°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.
Roane County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Roane County
How your county's soil matches Brussels Sprouts's growing requirements.
Soil pH
Your soil pH (5.3–6.5) is more acidic than Brussels Sprouts prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Roane 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 (2.9%). Annual compost additions will help Brussels Sprouts.
How to Plant Brussels Sprouts
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
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 | — | 4.1" | 0" | ❄️ Dormant |
| Feb | — | 4" | 0" | ❄️ Dormant |
| Mar | — | 4.8" | 0" | ❄️ Dormant |
| Apr | 3.9" | 4.7" | 0" | ✅ Rainfall sufficient |
| May | 3.9" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jun | 3.9" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 3.9" | 6.2" | 0" | ✅ Rainfall sufficient |
| Aug | 3.9" | 4.6" | 0" | ✅ Rainfall sufficient |
| Sep | 3.9" | 3.8" | 0.1" | 💧 Light watering |
| Oct | 3.9" | 4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 4.4" | 0" | ❄️ Dormant |
| Dec | — | 4.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Roane 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 Planting Timeline — Roane County, TN
Brussels Sprouts Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 5 | Mar 5 – Mar 19 |
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
| Direct Sow | March 26 | Mar 26 – Apr 16 |
| Harvest | July 9 | Jul 9 – Sep 3 |
| Fall Sowing | August 19 | Aug 19 – Sep 2 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Fall Sowing Harvest |
| 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: too_acidic
🗺️ USDA Zone
Zone 7b
📆 Growing Season
202 days in Roane County
Growing Tips for Brussels Sprouts in Roane County
Direct sow Brussels Sprouts outdoors after April 09 in Roane County when soil has warmed and frost danger has passed.
Summer highs in Roane County reach 92°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
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Check more plant combinations with our Companion Planting Checker →
Brussels Sprouts in Other Locations
Frequently Asked Questions
When should I plant Brussels Sprouts in Roane County, TN?
Roane County is in Zone 7b with an average last frost of April 9. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.
What planting zone is Roane County, TN?
Roane County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 9 and first fall frost is October 28.
Your Roane County Garden Planner — Free
A 24-page printable planner built for Roane 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.