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When to plant Ageratum in Spencer County, KY

Plant Ageratum in Spencer County after April 8; the prime window is April 8–April 29.

When to Plant Ageratum in Spencer County, KY

Spencer County, Kentucky Zone 6b June

June in Spencer County, Kentucky — your action list

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Spencer County, Kentucky.

Avg. last frost April 8
Avg. first frost October 29
Soil temp (4") 66°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. It's harvest week for ageratum

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  • First harvests: ageratum

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Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.

Spencer County, Kentucky is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 29, giving you a growing season of approximately 204 days.

At an elevation of 2,819 feet, Spencer County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Spencer County, KY (Zone 6b) Long season
204 days
Last Spring Frost April 8
204 growing days
First Fall Frost October 29

Spencer County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Feb 12 Transplant: Apr 2 🌸 Bloom: May 28 – Sep 10
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🌸 Bloom: Jun 3 – Sep 16
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🌸 Bloom: Jun 19 – Oct 2

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 Spencer County

How your county's soil matches Ageratum's growing requirements.

Soil pH

Your soil pH (5.3–6.7) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Spencer County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 204-day season

Sow every 6.9 weeks. Last sowing by Aug 15 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 302 gal / 100 sq ft

Monthly Watering Guide for Ageratum

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

Month Ageratum Needs Rainfall You Supplement Action
Jan 3" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 3.1" 1.2" 💧 Light watering
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

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

Ageratum 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.

Ageratum needs ~979 GDD — county provides 2,958 GDD Excellent fit

Ageratum Planting Timeline — Spencer County, KY

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 8 Apr 8 – Apr 29
Bloom June 3 Jun 3 – Sep 16

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

204 days in Spencer County

Growing Tips for Ageratum in Spencer County

Direct sow Ageratum outdoors after April 08 in Spencer County when soil has warmed and frost danger has passed.

Common pests for Ageratum in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Ageratum in Spencer County, KY?

Spencer County is in Zone 6b with an average last frost of April 8. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Spencer County, KY?

Spencer County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 29.

When should I plant Ageratum in Spencer County, KY?

In Spencer County, KY, plant Ageratum after the last frost (around April 8) and before the first frost (around October 29). Best results when soil holds above 50°F.

What growing zone is Spencer County, KY for Ageratum?

Spencer County sits in USDA Zone 6b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Spencer County's climate?

Yes — Ageratum grows well in Spencer County's temperate climate. Spencer County averages a 204-day frost-free season, with last frost around April 8 and first frost around October 29.

🌱

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A 22-page printable planner built for Spencer 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.

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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 Spencer County, KY. Local conditions may vary. Last updated: June 2026.

Sources & credits

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