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When to Plant Broccoli Rabe in Rusk County, WI

Rusk County, Wisconsin Zone 4a April

April in the garden — Rusk County, Wisconsin

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 16
Avg. first frost September 28
Soil temp (4") 42°F
Watering Low
Pest pressure Low
Daylight 13.3 hrs
A few tasks this April that'll pay off in May
  • Transplants going out: broccoli rabe
  • Direct-sowing: broccoli rabe

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Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

Rusk County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.

At an elevation of 1,112 feet, Rusk County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

Rusk County, WI (Zone 4a) Short season
135 days
Last Spring Frost May 16
135 growing days
First Fall Frost September 28
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Rusk County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 22 – Jul 27
Recommended (50%) ✓ Fits season (58 days to spare)
Start indoors: Apr 4 Transplant: May 16 🍅 Harvest: Jun 27 – Aug 1
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Apr 17 Transplant: May 29 🍅 Harvest: Jul 10 – Aug 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 Rusk County

How your county's soil matches Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (6.1–7.0) is within Broccoli Rabe's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Rusk County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.7%) — Broccoli Rabe will thrive.

How to Plant Broccoli Rabe

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 Broccoli Rabe

3
successive plantings in your 135-day season

Sow every 4.6 weeks. Last sowing by Jul 30 to harvest before frost.

For a dedicated fall crop, sow by Jul 06.

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

Monthly Watering Guide for Broccoli Rabe

Broccoli Rabe 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 Broccoli Rabe Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4" 0" ❄️ Dormant
May 3.5" 4.6" 0" ✅ Rainfall sufficient
Jun 3.5" 4.4" 0" ✅ Rainfall sufficient
Jul 3.5" 4.4" 0" ✅ Rainfall sufficient
Aug 3.5" 3.9" 0" ✅ Rainfall sufficient
Sep 3.5" 3.7" 0" ✅ Rainfall sufficient
Oct 2.8" 0" ❄️ Dormant
Nov 2.9" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Broccoli Rabe 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.

Broccoli Rabe needs ~500 GDD — county provides 1,350 GDD Excellent fit

Broccoli Rabe Planting Timeline — Rusk County, WI

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 9 May 9 – May 30
Harvest June 27 Jun 27 – Aug 1
Fall Sowing July 6 Jul 6 – Jul 20

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 Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4a

📆 Growing Season

135 days in Rusk County

Growing Tips for Broccoli Rabe in Rusk County

Direct sow Broccoli Rabe outdoors after May 16 in Rusk County when soil has warmed and frost danger has passed.

Common pests for Broccoli Rabe 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 when small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Broccoli Rabe in Rusk County, WI?

Rusk County is in Zone 4a with an average last frost of May 16. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rusk County, WI?

Rusk County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 16 and first fall frost is September 28.

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Your Rusk County Garden Planner — Free

A 24-page printable planner built for Rusk 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 Rusk County, WI. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.