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When to Plant Collard Greens in Sawyer County, WI

Sawyer County, Wisconsin Zone 4a May

Your May gardening checklist

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 17
Avg. first frost September 25
Soil temp (4") 50°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant collard greens outside

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

  2. Sow collard greens where they'll grow

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

To set up a strong June, finish these tasks
  • Starting indoors: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

Sawyer County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 25, giving you a growing season of approximately 131 days.

At an elevation of 815 feet, Sawyer County receives approximately 36.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Collard Greens to ensure they mature before fall.

Sawyer County, WI (Zone 4a) Short season
131 days
Last Spring Frost May 17
131 growing days
First Fall Frost September 25

Sawyer County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 10
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Jul 12 – Sep 13
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Jul 27 – Sep 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 Sawyer County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Collard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Collard Greens will thrive.

How to Plant Collard Greens

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Collard Greens

2
successive plantings in your 131-day season

Sow every 6.3 weeks. Last sowing by Jul 12 to harvest before frost.

For a dedicated fall crop, sow by Jul 03.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 3.5" 4.1" 0" ✅ Rainfall sufficient
Jun 3.5" 3.9" 0" ✅ Rainfall sufficient
Jul 3.5" 4" 0" ✅ Rainfall sufficient
Aug 3.5" 4" 0" ✅ Rainfall sufficient
Sep 3.5" 3.5" 0" ✅ Rainfall sufficient
Oct 3.1" 0" ❄️ Dormant
Nov 2.8" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Collard 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.

Collard Greens needs ~552 GDD — county provides 1,113 GDD Excellent fit

Collard Greens Planting Timeline — Sawyer County, WI

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest July 12 Jul 12 – Sep 13
Fall Sowing July 3 Jul 3 – Jul 17

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Sawyer County

Growing Tips for Collard Greens in Sawyer County

Direct sow Collard Greens outdoors after May 17 in Sawyer County when soil has warmed and frost danger has passed.

Common pests for Collard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Sawyer County, WI?

Sawyer County is in Zone 4a with an average last frost of May 17. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sawyer County, WI?

Sawyer County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 25.

🌱

Your Sawyer County Garden Planner — Free

A 24-page printable planner built for Sawyer County (Zone 4a). 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 Sawyer 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.