When to Plant Brussels Sprouts in Calvert County, MD
Top priorities for Calvert County, Maryland gardeners in May
Here's what deserves your attention in Calvert County, Maryland this month. Everything below is tailored to Zone 7b and timed around your local frost dates.
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Begin indoor sowing: brussels sprouts
You're about 26 weeks out from your last frost — the perfect window to get these germinating indoors.
Looking ahead to June
- First harvests: brussels sprouts
Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.
Calvert County, Maryland is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is November 10, giving you a growing season of approximately 225 days.
At an elevation of 539 feet, Calvert County receives approximately 46.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Brussels Sprouts during the growing season.
Calvert County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.9
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 Calvert County
How your county's soil matches Brussels Sprouts's growing requirements.
Soil pH
Your soil pH (5.5–6.9) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Calvert County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). 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 | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 3.4" | 0" | ❄️ Dormant |
| Mar | 3.9" | 3.6" | 0.3" | 💧 Light watering |
| Apr | 3.9" | 3.8" | 0.1" | 💧 Light watering |
| May | 3.9" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 3.9" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 3.9" | 5.1" | 0" | ✅ Rainfall sufficient |
| Aug | 3.9" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 3.9" | 4" | 0" | ✅ Rainfall sufficient |
| Oct | 3.9" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 3.9" | 3.2" | 0.7" | 💧 Light watering |
| Dec | — | 3.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Calvert 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 — Calvert County, MD
Brussels Sprouts Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 23 | Feb 23 – Mar 9 |
| Transplant Outdoors | March 30 | Mar 30 – Apr 13 |
| Direct Sow | March 16 | Mar 16 – Apr 6 |
| Harvest | June 29 | Jun 29 – Aug 24 |
| Fall Sowing | September 1 | Sep 1 – Sep 15 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · Only during dry spells
📅 Days to Maturity
90–130 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
225 days in Calvert County
Growing Tips for Brussels Sprouts in Calvert County
Direct sow Brussels Sprouts outdoors after March 30 in Calvert 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
Check more plant combinations with our Companion Planting Checker →
Brussels Sprouts in Other Locations
Frequently Asked Questions
When should I plant Brussels Sprouts in Calvert County, MD?
Calvert County is in Zone 7b with an average last frost of March 30. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.
What planting zone is Calvert County, MD?
Calvert County, Maryland is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is November 10.
Your Calvert County Garden Planner — Free
A 24-page printable planner built for Calvert 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.