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When to Plant Mizuna in Highland County, OH

Highland County, Ohio Zone 6b May

May in the garden — Highland County, Ohio

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Highland County, Ohio.

Avg. last frost April 22
Avg. first frost October 21
Soil temp (4") 61°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for mizuna

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. It's harvest week for 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.

Highland County, Ohio is in USDA Zone 6b. The average last spring frost is April 22 and the first fall frost is October 21, giving you a growing season of approximately 182 days.

At an elevation of 556 feet, Highland County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mizuna during the growing season.

Highland County, OH (Zone 6b) Moderate season
182 days
Last Spring Frost April 22
182 growing days
First Fall Frost October 21

Highland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jun 16
Recommended (50%) ✓ Fits season (119 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: May 27 – Jun 24
Safe Start (90%) ✓ Fits season (117 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jun 10 – Jul 8

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 Highland County

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

Soil pH

Your soil pH (5.8–7.1) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — 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

7
successive plantings in your 182-day season

Sow every 3.4 weeks. Last sowing by Sep 06 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 432 gal / 100 sq ft
Drought risk

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 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Highland 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 ~516 GDD — county provides 2,502 GDD Excellent fit

Mizuna Planting Timeline — Highland County, OH

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 8 Apr 8 – Apr 29
Harvest May 27 May 27 – Jun 24
Fall Sowing August 12 Aug 12 – Aug 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Harvest
June Harvest
July
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

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

182 days in Highland County

Growing Tips for Mizuna in Highland County

Direct sow Mizuna outdoors after April 22 in Highland County when soil has warmed and frost danger has passed.

Your generous 182.0-day season in Highland 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 Highland County, OH?

Highland County is in Zone 6b with an average last frost of April 22. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Highland County, OH?

Highland County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 22 and first fall frost is October 21.

🌱

Your Highland County Garden Planner — Free

A 24-page printable planner built for Highland 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.

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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 Highland County, OH. 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.