When to Plant Mizuna in Grant County, OR
May in the garden — Grant County, Oregon
Each item below is timed to Grant County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Scatter mizuna into prepared beds
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
To set up a strong June, finish these tasks
- Transplants going out: 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.
Grant County, Oregon is in USDA Zone 6b. The average last spring frost is June 6 and the first fall frost is September 10, giving you a growing season of approximately 96 days.
At an elevation of 2,838 feet, Grant County receives approximately 22.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mizuna to ensure they mature before fall.
Grant County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.4
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 Grant County
How your county's soil matches Mizuna's growing requirements.
Soil pH
Your soil pH (5.4–6.4) is more acidic than Mizuna prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Grant County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Mizuna.
Organic Matter
Organic matter is excellent (4.8%) — Mizuna will thrive.
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 Jul 27 to harvest before frost.
For a dedicated fall crop, sow by Jul 02.
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 | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.9" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 1.5" | 0" | ❄️ Dormant |
| May | — | 1.3" | 0" | ❄️ Dormant |
| Jun | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Jul | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Aug | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Sep | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 3.1" | 0" | ❄️ Dormant |
| Dec | — | 3.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Grant 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 — Grant County, OR
Mizuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 2 | May 2 – May 16 |
| Transplant Outdoors | June 6 | Jun 6 – Jun 20 |
| Direct Sow | May 23 | May 23 – Jun 13 |
| Harvest | July 11 | Jul 11 – Aug 8 |
| Fall Sowing | July 2 | Jul 2 – Jul 16 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
30–45 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
96 days in Grant County
Growing Tips for Mizuna in Grant County
Direct sow Mizuna outdoors after June 06 in Grant County when soil has warmed and frost danger has passed.
Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Grant County receives only 23" of rain annually. Mizuna needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Grant County, OR?
Grant County is in Zone 6b with an average last frost of June 6. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grant County, OR?
Grant County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 6 and first fall frost is September 10.
Your Grant County Garden Planner — Free
A 24-page printable planner built for Grant 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.