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When to Plant Ageratum in Fayette County, PA

Fayette County, Pennsylvania Zone 6b June

June to-do list for Fayette County, Pennsylvania

Welcome to June in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 27
Avg. first frost October 18
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
  1. Start ageratum indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Pick ageratum

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in July — start thinking about
  • 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.

Fayette County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 27 and the first fall frost is October 18, giving you a growing season of approximately 174 days.

At an elevation of 250 feet, Fayette County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Fayette County, PA (Zone 6b) Moderate season
174 days
Last Spring Frost April 27
174 growing days
First Fall Frost October 18

Fayette County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 28 Transplant: Apr 18 🌸 Bloom: Jun 13 – Sep 26
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Mar 9 Transplant: Apr 27 🌸 Bloom: Jun 22 – Oct 5
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Apr 3 Transplant: May 22 🌸 Bloom: Jul 17 – Oct 30

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 Fayette County

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

Soil pH

Your soil pH (5.1–6.3) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 174-day season

Sow every 6.9 weeks. Last sowing by Aug 04 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 16 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 3.1" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 3.2" 1.1" 💧 Light watering
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Fayette 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 ~1,232 GDD — county provides 3,175 GDD Excellent fit

Ageratum Planting Timeline — Fayette County, PA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 27 Apr 27 – May 18
Bloom June 22 Jun 22 – Oct 5

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6b

📆 Growing Season

174 days in Fayette County

Growing Tips for Ageratum in Fayette County

Direct sow Ageratum outdoors after April 27 in Fayette 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 Fayette County, PA?

Fayette County is in Zone 6b with an average last frost of April 27. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fayette County, PA?

Fayette County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 27 and first fall frost is October 18.

🌱

Your Fayette County Garden Planner — Free

A 22-page printable planner built for Fayette 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 Fayette County, PA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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