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When to Plant Mizuna in Lafayette County, WI

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.

Lafayette County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.

At an elevation of 665 feet, Lafayette County receives approximately 31.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Mizuna to ensure they mature before fall.

Lafayette County, WI (Zone 4b) Moderate season
164 days
Last Spring Frost April 28
164 growing days
First Fall Frost October 9

Lafayette County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (100 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🍅 Harvest: May 29 – Jun 26
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Jun 2 – Jun 30
Safe Start (90%) ✓ Fits season (98 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jun 16 – Jul 14

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 Lafayette County

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

Soil pH

Your soil pH (5.7โ€“7.3) overlaps with Mizuna's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Lafayette County is excellent for Mizuna โ€” 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

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

6
successive plantings in your 164-day season

Sow every 3.4 weeks. Last sowing by Aug 25 to harvest before frost.

For a dedicated fall crop, sow by Jul 17.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 334 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr 4.3" 3.1" 1.2" ๐Ÿ’ง Light watering
May 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jun 4.3" 4.4" 0" โœ… Rainfall sufficient
Jul 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Aug 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Sep 4.3" 2.9" 1.4" ๐Ÿ’ง Light watering
Oct 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Nov โ€” 1.8" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Lafayette County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 2,009 GDD Excellent fit

Mizuna Planting Timeline โ€” Lafayette County, WI

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 โ€“ Mar 31
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 2 Jun 2 โ€“ Jun 30
Fall Sowing July 17 Jul 17 โ€“ Jul 31

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

30โ€“45 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

164 days in Lafayette County

Growing Tips for Mizuna in Lafayette County

Direct sow Mizuna outdoors after April 28 in Lafayette County when soil has warmed and frost danger has passed.

Your generous 164.0-day season in Lafayette 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 Lafayette County, WI?

Lafayette County is in Zone 4b with an average last frost of April 28. Plan your Mizuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lafayette County, WI?

Lafayette County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lafayette County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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