Blog

When to plant Onion in Jackson County, KY

In Zone 6b (Jackson County), direct-sow Onion between April 3 and April 24 for spring, after the April 17 last-frost mark. A second sowing from August 14 to August 28 extends the harvest into fall.

When to Plant Onion in Jackson County, KY

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Jackson County, Kentucky is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 23, giving you a growing season of approximately 189 days.

At an elevation of 1,120 feet, Jackson County receives approximately 51 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Onion during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Jackson County, KY (Zone 6b) Moderate season
189 days
Last Spring Frost April 17
189 growing days
First Fall Frost October 23

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.6

Drainage

Well Drained

Monthly Watering Guide for Onion

Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Onion Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 4.4" 0" ❄️ Dormant
Mar 5.2" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

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

Onion Planting Timeline — Jackson County, KY

Onion Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 3 Apr 3 – Apr 24
Harvest July 17 Jul 17 – Sep 4
Fall Sowing August 14 Aug 14 – Aug 28

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

189 days in Jackson County

Growing Tips for Jackson County

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Jackson County, KY?

Jackson County is in Zone 6b with an average last frost of April 17. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jackson County, KY?

Jackson County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 23.

When should I plant Onion in Jackson County, KY?

In Jackson County, KY, plant Onion after the last frost (around April 17) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Jackson County, KY for Onion?

Jackson County sits in USDA Zone 6b. Onion grows reliably in zones 3a through 10b, so it's a good fit here.

Can Onion grow in Jackson County's climate?

Yes — Onion grows well in Jackson County's temperate climate. Jackson County averages a 189-day frost-free season, with last frost around April 17 and first frost around October 23.

🌱

Your Jackson County Garden Planner — Free

A 22-page printable planner built for Jackson County (Zone 6b). 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 Jackson County, KY. Local conditions may vary. Last updated: July 2026.

Sources & credits

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