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When to Plant Mizuna in Ottawa County, KS

Ottawa County, Kansas Zone 6b May

Your May game plan for Ottawa County, Kansas

Here's what deserves your attention in Ottawa County, Kansas this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 14
Avg. first frost October 23
Soil temp (4") 59°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for mizuna

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Collect mizuna at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

June prep starts now
  • 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.

Ottawa County, Kansas is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 23, giving you a growing season of approximately 192 days.

At an elevation of 993 feet, Ottawa County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Mizuna during the growing season.

Ottawa County, KS (Zone 6b) Moderate season
192 days
Last Spring Frost April 14
192 growing days
First Fall Frost October 23
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Ottawa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 16 – Jun 13
Recommended (50%) ✓ Fits season (129 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jun 16
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 1 – Jun 29

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 Ottawa County

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

Soil pH

Your soil pH (6.8–7.6) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 192-day season

Sow every 3.4 weeks. Last sowing by Sep 08 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 974 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 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 4.3" 2.4" 1.9" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 3.5" 0.8" 💧 Light watering
Jul 4.3" 3.1" 1.2" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa 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 2,640 GDD Excellent fit

Mizuna Planting Timeline — Ottawa County, KS

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest May 19 May 19 – Jun 16
Fall Sowing August 14 Aug 14 – Aug 28

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
October
November
December
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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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

192 days in Ottawa County

Growing Tips for Mizuna in Ottawa County

Direct sow Mizuna outdoors after April 14 in Ottawa County when soil has warmed and frost danger has passed.

Your generous 192.0-day season in Ottawa 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.

Ottawa County receives only 24" 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

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Ottawa County, KS?

Ottawa County is in Zone 6b with an average last frost of April 14. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, KS?

Ottawa County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 23.

🌱

Your Ottawa County Garden Planner — Free

A 24-page printable planner built for Ottawa 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Ottawa County, KS. 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.