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When to plant Ageratum in Trigg County, KY

Trigg County's spring Ageratum window runs April 5 through April 26. most warm-season crops establish quickly once soil holds above 60°F.

When to Plant Ageratum in Trigg County, KY

Trigg County, Kentucky Zone 7a August

Your August planting checklist for Trigg County, Kentucky

Your garden in Trigg County, Kentucky is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost April 5
Avg. first frost October 30
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Pick ageratum

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

September will be here before you know it — start on
  • 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.

Trigg County, Kentucky is in USDA Zone 7a. The average last spring frost is April 5 and the first fall frost is October 30, giving you a growing season of approximately 208 days.

At an elevation of 1,825 feet, Trigg County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Trigg County, KY (Zone 7a) Long season
208 days
Last Spring Frost April 5
208 growing days
First Fall Frost October 30

Trigg County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.8

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Feb 16 Transplant: Mar 30 🌸 Bloom: May 25 – Sep 14
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Feb 22 Transplant: Apr 5 🌸 Bloom: May 31 – Sep 20
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Mar 7 Transplant: Apr 18 🌸 Bloom: Jun 13 – Oct 3

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 Trigg County

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

Soil pH

Your soil pH (5.2–6.8) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 208-day season

Sow every 6.9 weeks. Last sowing by Aug 16 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 23 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 3.7" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 4.7" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 5.7" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Trigg 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 ~1,080 GDD — county provides 3,328 GDD Excellent fit

Ageratum Planting Timeline — Trigg County, KY

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors April 5 Apr 5 – Apr 19
Direct Sow April 5 Apr 5 – Apr 26
Bloom May 31 May 31 – Sep 20

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Bloom
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 7a

📆 Growing Season

208 days in Trigg County

Growing Tips for Ageratum in Trigg County

Direct sow Ageratum outdoors after April 05 in Trigg 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 Trigg County, KY?

Trigg County is in Zone 7a with an average last frost of April 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Trigg County, KY?

Trigg County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 5 and first fall frost is October 30.

When should I plant Ageratum in Trigg County, KY?

In Trigg County, KY, plant Ageratum after the last frost (around April 5) and before the first frost (around October 30). Best results when soil holds above 50°F.

What growing zone is Trigg County, KY for Ageratum?

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

Can Ageratum grow in Trigg County's climate?

Yes — Ageratum grows well in Trigg County's temperate climate. Trigg County averages a 208-day frost-free season, with last frost around April 5 and first frost around October 30.

🌱

Your Trigg County Garden Planner — Free

A 22-page printable planner built for Trigg 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 Trigg County, KY. Local conditions may vary. Last updated: August 2026.

Sources & credits

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