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When to Plant Ageratum in Putnam County, OH

Putnam County, Ohio Zone 6a June

Your June gardening checklist

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

Avg. last frost April 23
Avg. first frost October 22
Soil temp (4") 67°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Sow ageratum in trays indoors

    These need a head start before your last frost (April 23). Sow into cells now so you're ready to transplant in a few weeks.

  2. Pick ageratum

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Before July arrives, get these ready
  • 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.

Putnam County, Ohio is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 22, giving you a growing season of approximately 182 days.

At an elevation of 1,300 feet, Putnam County receives approximately 40.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Ageratum to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Putnam County, OH (Zone 6a) Moderate season
182 days
Last Spring Frost April 23
182 growing days
First Fall Frost October 22

Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Feb 25 Transplant: Apr 15 🌸 Bloom: Jun 10 – Sep 16
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 5 Transplant: Apr 23 🌸 Bloom: Jun 18 – Sep 24
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Mar 18 Transplant: May 6 🌸 Bloom: Jul 1 – Oct 7

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 Putnam County

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

Soil pH

Your soil pH (6.3–6.7) is within Ageratum's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Ageratum will thrive.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 182-day season

Sow every 6.9 weeks. Last sowing by Aug 08 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 136 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.8" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 ~878 GDD — county provides 2,366 GDD Excellent fit

Ageratum Planting Timeline — Putnam County, OH

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 23 Apr 23 – May 14
Bloom June 18 Jun 18 – Sep 24

· 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

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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

182 days in Putnam County

Growing Tips for Ageratum in Putnam County

Direct sow Ageratum outdoors after April 23 in Putnam 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 Putnam County, OH?

Putnam County is in Zone 6a with an average last frost of April 23. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, OH?

Putnam County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 22.

🌱

Your Putnam County Garden Planner — Free

A 22-page printable planner built for Putnam 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 Putnam County, OH. 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.