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When to Plant Mizuna in Chippewa County, WI

Chippewa County, Wisconsin Zone 4b May

This month in Chippewa County, Wisconsin

Your Chippewa County, Wisconsin garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 15
Avg. first frost September 28
Soil temp (4") 53°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant mizuna

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Seed mizuna outdoors

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

A few tasks this May that'll pay off in June
  • Starting indoors: mizuna
  • 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.

Chippewa County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 28, giving you a growing season of approximately 136 days.

At an elevation of 916 feet, Chippewa County receives approximately 40.4 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.

Chippewa County, WI (Zone 4b) Short season
136 days
Last Spring Frost May 15
136 growing days
First Fall Frost September 28

Chippewa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 15 – Jul 13
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jun 19 – Jul 17
Safe Start (90%) ✓ Fits season (77 days to spare)
Start indoors: Apr 14 Transplant: May 26 🍅 Harvest: Jun 30 – Jul 28

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 Chippewa County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Chippewa 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 (4.4%) — Mizuna will thrive.

How to Plant Mizuna

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

5
successive plantings in your 136-day season

Sow every 3.4 weeks. Last sowing by Aug 14 to harvest before frost.

For a dedicated fall crop, sow by Jul 06.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 63 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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 4.3" 0" ✅ Rainfall sufficient
Oct 3.4" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Chippewa 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 ~459 GDD — county provides 1,666 GDD Excellent fit

Mizuna Planting Timeline — Chippewa County, WI

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest June 19 Jun 19 – Jul 17
Fall Sowing July 6 Jul 6 – Jul 20

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August
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 4b

📆 Growing Season

136 days in Chippewa County

Growing Tips for Mizuna in Chippewa County

Direct sow Mizuna outdoors after May 15 in Chippewa County when soil has warmed and frost danger has passed.

Your generous 136.0-day season in Chippewa 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 Chippewa County, WI?

Chippewa County is in Zone 4b with an average last frost of May 15. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chippewa County, WI?

Chippewa County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 28.

🌱

Your Chippewa County Garden Planner — Free

A 24-page printable planner built for Chippewa County (Zone 4b). 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 Chippewa County, WI. 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.