Blog

When to Plant Mustard Greens in Marinette County, WI

Marinette County, Wisconsin Zone 4b May

This month in Marinette County, Wisconsin

Here's what deserves your attention in Marinette County, Wisconsin this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 18
Avg. first frost October 1
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant mustard greens

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Outdoor sowing time: mustard greens

    Your soil is 55°F — warm enough for these to germinate without babying.

June will be here before you know it — start on
  • Starting indoors: mustard greens
  • First harvests: mustard greens

Instant PDF download. No spam, unsubscribe any time.

Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Marinette County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 18 and the first fall frost is October 1, giving you a growing season of approximately 136 days.

At an elevation of 782 feet, Marinette County receives approximately 31.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall.

Marinette County, WI (Zone 4b) Short season
136 days
Last Spring Frost May 18
136 growing days
First Fall Frost October 1
Share this guide:

Marinette County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 15 – Aug 17
Recommended (50%) ✓ Fits season (38 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jun 22 – Aug 24
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Jul 4 – Sep 5

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 Marinette County

How your county's soil matches Mustard Greens's growing requirements.

Soil pH

Your soil pH (5.8–7.3) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Mustard Greens will thrive.

How to Plant Mustard Greens

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 Mustard Greens

5
successive plantings in your 136-day season

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

For a dedicated fall crop, sow by Jul 09.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Mustard Greens

Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mustard Greens Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 3" 3.8" 0" ✅ Rainfall sufficient
Jun 3" 4.4" 0" ✅ Rainfall sufficient
Jul 3" 3.2" 0" ✅ Rainfall sufficient
Aug 3" 3.1" 0" ✅ Rainfall sufficient
Sep 3" 2.6" 0.4" 💧 Light watering
Oct 3" 2.4" 0.6" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Marinette County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mustard Greens 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.

Mustard Greens needs ~490 GDD — county provides 1,666 GDD Excellent fit

Mustard Greens Planting Timeline — Marinette County, WI

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest June 22 Jun 22 – Aug 24
Fall Sowing July 9 Jul 9 – Jul 23

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 Transplant Outdoors Direct Sow Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

136 days in Marinette County

Growing Tips for Mustard Greens in Marinette County

Direct sow Mustard Greens outdoors after May 18 in Marinette County when soil has warmed and frost danger has passed.

Your generous 136.0-day season in Marinette County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.

Common pests for Mustard Greens 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 early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mustard Greens in Marinette County, WI?

Marinette County is in Zone 4b with an average last frost of May 18. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marinette County, WI?

Marinette County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 18 and first fall frost is October 1.

🌱

Your Marinette County Garden Planner — Free

A 24-page printable planner built for Marinette 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.

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 Marinette 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.