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When to Plant Broccoli in Boone County, KY

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Boone County, Kentucky is in USDA Zone 6a. The average last spring frost is April 19 and the first fall frost is October 21, giving you a growing season of approximately 185 days.

At an elevation of 2,587 feet, Boone County receives approximately 51 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Broccoli during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Broccoli root diseases.

Boone County, KY (Zone 6a) Moderate season
185 days
Last Spring Frost April 19
185 growing days
First Fall Frost October 21

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jun 13 – Jul 25
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 2
Safe Start (90%) ✓ Fits season (72 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 11 – Aug 22

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.

Plant Water Budget

Plant needs
1.0″/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 โ€” consider drought-tolerant varieties and mulching

Broccoli needs ~1,256 GDD — county provides 3,098 GDD Excellent fit

Broccoli Planting Timeline โ€” Boone County, KY

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors April 19 Apr 19 โ€“ May 3
Direct Sow April 5 Apr 5 โ€“ Apr 26
Fall Sowing August 12 Aug 12 โ€“ Aug 26
Harvest June 21 Jun 21 โ€“ Aug 2

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 Transplant Outdoors
June Harvest
July Harvest
August Fall Sowing Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

185 days

Growing Tips for Boone County

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

๐ŸŒพ Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial โ€” must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Boone County, KY?

Boone County is in Zone 6a with an average last frost of April 19. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Boone County, KY?

Boone County, Kentucky is in USDA Hardiness Zone 6a. The average last spring frost is April 19 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

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