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When to Plant Broccoli Rabe in Java, SD

Java, SD Zone 4b June

Your June game plan for Java, SD

Your Java, SD garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 10
Avg. first frost October 1
Soil temp (4") 64°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Get broccoli rabe seeds going inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Basket week: broccoli rabe

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this June that'll pay off in July
  • First harvests: broccoli rabe
  • Fall 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.

Java, South Dakota is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 1, giving you a growing season of approximately 144 days.

At an elevation of 1,070 feet, Walworth County receives approximately 30.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

Java, SD (Zone 4b) Short season
144 days
Last Spring Frost May 10
144 growing days
First Fall Frost October 1
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Java Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Broccoli Rabe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jun 12 – Jul 17
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jun 21 – Jul 26
Safe Start (90%) ✓ Fits season (68 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jun 30 – Aug 4

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 Java

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

Soil pH

Your soil pH (6.5–7.8) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Broccoli Rabe.

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

4
successive plantings in your 144-day season

Sow every 4.6 weeks. Last sowing by Aug 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 09.

Broccoli Rabe Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/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 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 2.1" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 3.5" 3.8" 0" ✅ Rainfall sufficient
Jun 3.5" 1.9" 1.6" 💧 Light watering
Jul 3.5" 2.7" 0.8" 💧 Light watering
Aug 3.5" 2.8" 0.7" 💧 Light watering
Sep 3.5" 2.6" 0.9" 💧 Light watering
Oct 3.5" 2.8" 0.7" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Walworth 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 ~575 GDD — county provides 1,656 GDD Excellent fit

Broccoli Rabe Planting Timeline — Java, SD

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Harvest June 21 Jun 21 – Jul 26
Fall Sowing July 9 Jul 9 – Jul 23

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

144 days in Walworth County

Growing Tips for Broccoli Rabe in Java

Direct sow Broccoli Rabe outdoors after May 10 in Walworth 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 →

🌱

Your Walworth County Garden Planner — Free

A 22-page printable planner built for Walworth 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 Walworth County, SD. Local conditions may vary. Last updated: June 2026.