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When to Plant Broccoli Rabe in Rockcastle County, KY

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

Rockcastle County, Kentucky is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 23, giving you a growing season of approximately 190 days.

At an elevation of 1,677 feet, Rockcastle County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Broccoli Rabe during the growing season.

Rockcastle County, KY (Zone 6b) Moderate season
190 days
Last Spring Frost April 16
190 growing days
First Fall Frost October 23

Rockcastle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (116 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 20 – Jun 24
Recommended (50%) ✓ Fits season (113 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: May 28 – Jul 2
Safe Start (90%) ✓ Fits season (108 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jun 12 – Jul 17

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 Rockcastle County

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

Soil pH

Your soil pH (5.3โ€“6.9) overlaps with Broccoli Rabe's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Rockcastle County is excellent for Broccoli Rabe โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Broccoli Rabe.

How to Plant Broccoli Rabe

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Broccoli Rabe

5
successive plantings in your 190-day season

Sow every 4.6 weeks. Last sowing by Aug 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/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 โ€” 3.1" 0" โ„๏ธ Dormant
Feb โ€” 3.6" 0" โ„๏ธ Dormant
Mar โ€” 4.1" 0" โ„๏ธ Dormant
Apr 3.5" 3.4" 0.1" ๐Ÿ’ง Light watering
May 3.5" 3" 0.5" ๐Ÿ’ง Light watering
Jun 3.5" 3.5" 0" โœ… Rainfall sufficient
Jul 3.5" 3.9" 0" โœ… Rainfall sufficient
Aug 3.5" 3.8" 0" โœ… Rainfall sufficient
Sep 3.5" 3.2" 0.3" ๐Ÿ’ง Light watering
Oct 3.5" 3.1" 0.4" ๐Ÿ’ง Light watering
Nov โ€” 3.3" 0" โ„๏ธ Dormant
Dec โ€” 3.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Rockcastle County). Supplement amounts are based on average rainfall โ€” 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" 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.

Broccoli Rabe needs ~912 GDD — county provides 3,467 GDD Excellent fit

Broccoli Rabe Planting Timeline โ€” Rockcastle County, KY

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Direct Sow April 2 Apr 2 โ€“ Apr 23
Harvest May 28 May 28 โ€“ Jul 2
Fall Sowing August 14 Aug 14 โ€“ Aug 28

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

190 days in Rockcastle County

Growing Tips for Broccoli Rabe in Rockcastle County

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

Your generous 190.0-day season in Rockcastle County allows multiple plantings of Broccoli Rabe. Sow every 20.0 days for continuous harvest.

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 Rockcastle County, KY?

Rockcastle County is in Zone 6b with an average last frost of April 16. Plan your Broccoli Rabe planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rockcastle County, KY?

Rockcastle County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rockcastle County gardeners in Zone 6b 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 Rockcastle County, KY. Local conditions may vary. Last updated: April 2026.