When to Plant Mitsuba in Northumberland County, PA
May in the garden — Northumberland County, Pennsylvania
Here's what deserves your attention in Northumberland County, Pennsylvania this month. Everything below is tailored to Zone 6b and timed around your local frost dates.
-
Get mitsuba seeds going inside
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
Coming up in June — start thinking about
- First harvests: mitsuba
Mitsuba (Japanese parsley) is a shade-loving herb with trefoil leaves and a mild celery-parsley flavor. It is essential in Japanese cuisine for soups, salads, and garnishes.
Northumberland County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 26, giving you a growing season of approximately 192 days.
At an elevation of 324 feet, Northumberland County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Mitsuba during the growing season.
Northumberland County Soil Profile
Soil Type
Silt Loam
Soil pH
5.1-6.6
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 Northumberland County
How your county's soil matches Mitsuba's growing requirements.
Soil pH
Your soil pH (5.1–6.6) is more acidic than Mitsuba prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Northumberland County is excellent for Mitsuba — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Mitsuba.
How to Plant Mitsuba
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Mitsuba
Sow every 5.7 weeks. Last sowing by Aug 17 to harvest before frost.
For a dedicated fall crop, sow by Aug 17.
Plant Water Budget
Monthly Watering Guide for Mitsuba
Mitsuba needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Mitsuba Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 3.3" | 1" | 💧 Light watering |
| Oct | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Northumberland County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mitsuba 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.
Mitsuba Planting Timeline — Northumberland County, PA
Mitsuba Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 13 | Mar 13 – Mar 27 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Direct Sow | April 3 | Apr 3 – Apr 24 |
| Harvest | June 5 | Jun 5 – Jul 31 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
192 days in Northumberland County
Growing Tips for Mitsuba in Northumberland County
Direct sow Mitsuba outdoors after April 17 in Northumberland County when soil has warmed and frost danger has passed.
Common pests for Mitsuba in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow or start indoors in partial shade. Mitsuba prefers cool, moist conditions. Harvest outer stems as needed. Self-sows readily in shaded garden areas.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Mitsuba in Other Locations
Frequently Asked Questions
When should I plant Mitsuba in Northumberland County, PA?
Northumberland County is in Zone 6b with an average last frost of April 17. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.
What planting zone is Northumberland County, PA?
Northumberland County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 26.
Your Northumberland County Garden Planner — Free
A 24-page printable planner built for Northumberland County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.