When to Plant Mizuna in Howard County, MD
This month in Howard County, Maryland
A quick May briefing for Howard County, Maryland gardeners — what's urgent, what's next, and what can wait.
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Get mizuna seeds going inside
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
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Harvest mizuna as they ripen
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Coming up in June — start thinking about
- First harvests: mizuna
Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.
Howard County, Maryland is in USDA Zone 7b. The average last spring frost is April 8 and the first fall frost is November 1, giving you a growing season of approximately 207 days.
At an elevation of 753 feet, Howard County receives approximately 48.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Mizuna during the growing season.
Howard County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-7
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 Howard County
How your county's soil matches Mizuna's growing requirements.
Soil pH
Your soil pH (5.6–7.0) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Howard County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Mizuna.
Organic Matter
Organic matter is moderate (3.2%). Annual compost additions will help Mizuna.
How to Plant Mizuna
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Mizuna
Sow every 3.4 weeks. Last sowing by Sep 17 to harvest before frost.
For a dedicated fall crop, sow by Aug 23.
Plant Water Budget
Monthly Watering Guide for Mizuna
Mizuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Mizuna Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.6" | 0" | ❄️ Dormant |
| Feb | — | 3.4" | 0" | ❄️ Dormant |
| Mar | — | 4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jun | 4.3" | 5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Sep | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Oct | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Nov | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Howard County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mizuna 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.
Mizuna Planting Timeline — Howard County, MD
Mizuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 4 | Mar 4 – Mar 18 |
| Transplant Outdoors | April 8 | Apr 8 – Apr 22 |
| Direct Sow | March 25 | Mar 25 – Apr 15 |
| Harvest | May 13 | May 13 – Jun 10 |
| Fall Sowing | August 23 | Aug 23 – Sep 6 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
30–45 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
207 days in Howard County
Growing Tips for Mizuna in Howard County
Direct sow Mizuna outdoors after April 08 in Howard County when soil has warmed and frost danger has passed.
Your generous 207.0-day season in Howard County allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.
Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mizuna in Other Locations
Frequently Asked Questions
When should I plant Mizuna in Howard County, MD?
Howard County is in Zone 7b with an average last frost of April 8. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Howard County, MD?
Howard County, Maryland is in USDA Hardiness Zone 7b. The average last spring frost is April 8 and first fall frost is November 1.
Your Howard County Garden Planner — Free
A 24-page printable planner built for Howard 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.