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When to Plant Mizuna in Adair County, OK

Adair County, Oklahoma Zone 7b May

May in the garden — Adair County, Oklahoma

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 7
Avg. first frost October 27
Soil temp (4") 66°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Sow mizuna in trays indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Basket week: mizuna

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Before June arrives, get these ready
  • First harvests: mizuna

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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.

Adair County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is October 27, giving you a growing season of approximately 203 days.

At an elevation of 486 feet, Adair County receives approximately 33.9 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Mizuna during the growing season.

Adair County, OK (Zone 7b) Long season
203 days
Last Spring Frost April 7
203 growing days
First Fall Frost October 27
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Adair County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (146 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 2 – May 30
Recommended (50%) ✓ Fits season (140 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: May 12 – Jun 9
Safe Start (90%) ✓ Fits season (146 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: May 30 – Jun 27

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 Adair County

How your county's soil matches Mizuna's growing requirements.

Soil pH

Your soil pH (6.7–7.1) is within Mizuna's preferred range (6.0–7.5).

Soil Texture

The loam soil in Adair County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.1%) — Mizuna will thrive.

How to Plant Mizuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

8
successive plantings in your 203-day season

Sow every 3.4 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 540 gal / 100 sq ft

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 1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adair 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 needs ~741 GDD — county provides 4,009 GDD Excellent fit

Mizuna Planting Timeline — Adair County, OK

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow March 24 Mar 24 – Apr 14
Harvest May 12 May 12 – Jun 9
Fall Sowing August 18 Aug 18 – Sep 1

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
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
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

203 days in Adair County

Growing Tips for Mizuna in Adair County

Direct sow Mizuna outdoors after April 07 in Adair County when soil has warmed and frost danger has passed.

Your generous 203.0-day season in Adair 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

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Adair County, OK?

Adair County is in Zone 7b with an average last frost of April 7. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adair County, OK?

Adair County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is October 27.

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Your Adair County Garden Planner — Free

A 24-page printable planner built for Adair 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Adair County, OK. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.