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When to plant Zinnia in Simpson County, KY

Simpson County sits in USDA Zone 7a. Plant Zinnia between April 6 (after last frost on April 6) and April 27.

When to Plant Zinnia in Simpson County, KY

Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Simpson County, Kentucky is in USDA Zone 7a. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 3,996 feet, Simpson County receives approximately 49.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Zinnia during the growing season.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Simpson County, KY (Zone 7a) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Simpson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Zinnia Planting Timeline — Simpson County, KY

Zinnia Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow April 6 Apr 6 – Apr 27
Bloom June 15 Jun 15 – Oct 5

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 7a

📆 Growing Season

206 days in Simpson County

Growing Tips for Simpson County

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zinnia in Simpson County, KY?

Simpson County is in Zone 7a with an average last frost of April 6. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Simpson County, KY?

Simpson County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 6 and first fall frost is October 29.

When should I plant Zinnia in Simpson County, KY?

In Simpson County, KY, plant Zinnia after the last frost (around April 6) and before the first frost (around October 29). Best results when soil holds above 50°F.

What growing zone is Simpson County, KY for Zinnia?

Simpson County sits in USDA Zone 7a. Zinnia grows reliably in zones 3a through 11b, so it's a good fit here.

Can Zinnia grow in Simpson County's climate?

Yes — Zinnia grows well in Simpson County's temperate climate. Simpson County averages a 206-day frost-free season, with last frost around April 6 and first frost around October 29.

🌱

Your Simpson County Garden Planner — Free

A 22-page printable planner built for Simpson County (Zone 7a). 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 Simpson County, KY. Local conditions may vary. Last updated: June 2026.

Sources & credits

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