When to Plant Mizuna in Seminole County, OK
May in Seminole County, Oklahoma — your action list
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Seminole County, Oklahoma.
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Start mizuna indoors
You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.
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Start harvesting mizuna
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
To set up a strong June, finish these tasks
- 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.
Seminole County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 6, giving you a growing season of approximately 220 days.
At an elevation of 961 feet, Seminole County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Mizuna during the growing season.
Seminole County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.5
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 Seminole County
How your county's soil matches Mizuna's growing requirements.
Soil pH
Your soil pH (6.7–7.5) is within Mizuna's preferred range (6.0–7.5).
Soil Texture
The loam soil in Seminole County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). 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 22 to harvest before frost.
For a dedicated fall crop, sow by Aug 28.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Apr | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| May | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Jun | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jul | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Aug | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Nov | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Dec | — | 0.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Seminole 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 — Seminole County, OK
Mizuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | March 31 | Mar 31 – Apr 14 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | May 5 | May 5 – Jun 2 |
| Fall Sowing | August 28 | Aug 28 – Sep 11 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors 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 · 2-3 times/week
📅 Days to Maturity
30–45 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 7b
📆 Growing Season
220 days in Seminole County
Growing Tips for Mizuna in Seminole County
Direct sow Mizuna outdoors after March 31 in Seminole County when soil has warmed and frost danger has passed.
Your generous 220.0-day season in Seminole 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.
Seminole County receives only 21" 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 Seminole County, OK?
Seminole County is in Zone 7b with an average last frost of March 31. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Seminole County, OK?
Seminole County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 6.
Your Seminole County Garden Planner — Free
A 24-page printable planner built for Seminole 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.