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When to plant Ageratum in Windham County County,

Aim to plant Ageratum in Windham County County on or after April 29; the window stays open through May 20. Windham County County's 170-day frost-free season gives you a single solid spring crop with a brief fall option.

When to Plant Ageratum in Windham County, CT

Windham County, Connecticut Zone 6a June

Your June game plan for Windham County, Connecticut

A quick June briefing for Windham County, Connecticut gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 29
Avg. first frost October 16
Soil temp (4") 73°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
  1. Get ageratum seeds going inside

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

  2. It's harvest week for ageratum

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

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.

Windham County, Connecticut is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 16, giving you a growing season of approximately 170 days.

At an elevation of 110 feet, Windham County receives approximately 41.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Windham County, CT (Zone 6a) Moderate season
170 days
Last Spring Frost April 29
170 growing days
First Fall Frost October 16
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Windham County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🌸 Bloom: Jun 17 – Sep 23
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 24 – Sep 30
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Mar 27 Transplant: May 15 🌸 Bloom: Jul 10 – Oct 16

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 Windham County

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

Soil pH

Your soil pH (5.1–6.7) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 170-day season

Sow every 6.9 weeks. Last sowing by Aug 02 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 3.2" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Windham 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 ~928 GDD — county provides 2,337 GDD Excellent fit

Ageratum Planting Timeline — Windham County, CT

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 29 Apr 29 – May 20
Bloom June 24 Jun 24 – Sep 30

· 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
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

170 days in Windham County

Growing Tips for Ageratum in Windham County

Direct sow Ageratum outdoors after April 29 in Windham 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 Windham County, CT?

Windham County is in Zone 6a with an average last frost of April 29. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Windham County, CT?

Windham County, Connecticut is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 16.

When should I plant Ageratum in Windham County County, ?

In Windham County County, , plant Ageratum after the last frost (around April 29) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Windham County County, for Ageratum?

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

Can Ageratum grow in Windham County County's climate?

Yes — Ageratum grows well in Windham County County's temperate climate. Windham County County averages a 170-day frost-free season, with last frost around April 29 and first frost around October 16.

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Your Windham County Garden Planner — Free

A 22-page printable planner built for Windham 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 Windham County, CT. 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.