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When to Plant Ageratum in Venango County, PA

Venango County, Pennsylvania Zone 6a June

This month in Venango County, Pennsylvania

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 5
Avg. first frost October 18
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Get ageratum seeds going inside

    Label every cell. You will absolutely forget which is which otherwise.

  2. Start harvesting ageratum

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong July, finish these tasks
  • 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.

Venango County, Pennsylvania is in USDA Zone 6a. The average last spring frost is May 5 and the first fall frost is October 18, giving you a growing season of approximately 166 days.

At an elevation of 1,166 feet, Venango County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Venango County, PA (Zone 6a) Moderate season
166 days
Last Spring Frost May 5
166 growing days
First Fall Frost October 18
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Venango County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 24 – Sep 30
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Mar 17 Transplant: May 5 🌸 Bloom: Jun 30 – Oct 6
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Mar 30 Transplant: May 18 🌸 Bloom: Jul 13 – Oct 19

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 Venango County

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

Soil pH

Your soil pH (5.2–6.4) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 166-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
Watering frequency Natural rainfall sufficient
Season total 0 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 3.3" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Venango 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 ~1,029 GDD — county provides 2,531 GDD Excellent fit

Ageratum Planting Timeline — Venango County, PA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 5 May 5 – May 19
Direct Sow May 5 May 5 – May 26
Bloom June 30 Jun 30 – Oct 6

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

166 days in Venango County

Growing Tips for Ageratum in Venango County

Direct sow Ageratum outdoors after May 05 in Venango 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 Venango County, PA?

Venango County is in Zone 6a with an average last frost of May 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Venango County, PA?

Venango County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is May 5 and first fall frost is October 18.

🌱

Your Venango County Garden Planner — Free

A 22-page printable planner built for Venango County (Zone 6a). 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 Venango 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.