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When to Plant Phlox in Logan County, OH

Logan County, Ohio Zone 6a June

June in the garden — Logan County, Ohio

We've pulled the most time-sensitive tasks for Logan County, Ohio this June and put them front and centre. Tackle them in order.

Avg. last frost April 24
Avg. first frost October 19
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start phlox under lights

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Looking ahead to July
  • First harvests: phlox

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Garden Phlox (Phlox paniculata) is a beloved native perennial of eastern North America, producing large, domed clusters of fragrant flowers atop upright stems from mid-summer into fall. Its sweet honey-like fragrance carries on summer evenings and draws hummingbirds, butterflies, and sphinx moths. Modern cultivars offer colors spanning white, pink, salmon, red, purple, and bicolors. A classic cottage garden stalwart, phlox combines well with black-eyed Susans, echinacea, and ornamental grasses in naturalistic plantings. Select mildew-resistant cultivars for best long-term performance.

Logan County, Ohio is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 19, giving you a growing season of approximately 178 days.

At an elevation of 829 feet, Logan County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Phlox to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Logan County, OH (Zone 6a) Moderate season
178 days
Last Spring Frost April 24
178 growing days
First Fall Frost October 19
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Logan County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🌸 Bloom: Jul 2 – Sep 24
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Feb 20 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 2
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Mar 9 Transplant: May 18 🌸 Bloom: Jul 27 – 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 Logan County

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

Soil pH

Your soil pH (6.1–7.2) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Phlox will thrive.

How to Plant Phlox

0.3"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Phlox

2
successive plantings in your 178-day season

Sow every 9.1 weeks. Last sowing by Jul 01 to harvest before frost.

Phlox 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 165 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Phlox

Phlox needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Phlox Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Logan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Phlox 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.

Phlox needs ~1,164 GDD — county provides 2,180 GDD Excellent fit

Phlox Planting Timeline — Logan County, OH

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors May 1 May 1 – May 15
Direct Sow May 1 May 1 – May 22
Bloom July 10 Jul 10 – Oct 2

Plant 0.3" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
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 · Only during dry spells

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

178 days in Logan County

Growing Tips for Phlox in Logan County

Direct sow Phlox outdoors after April 24 in Logan County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost, or transplant container divisions in spring. Named cultivar seeds may not come true; divisions from named plants are the preferred propagation method. Space generously (18–24 inches) and avoid overhead watering to reduce powdery mildew risk. Good air circulation is critical — thin clumps to the strongest 5–7 stems per plant in spring. Deadhead after the primary bloom flush to encourage secondary flowering. Division every 2–3 years in spring keeps plants vigorous. Fall planting of divisions (Zones 5+) is equally effective. Year 2+ plants develop into full clumps with the most prolific bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Phlox in Logan County, OH?

Logan County is in Zone 6a with an average last frost of April 24. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Logan County, OH?

Logan County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 19.

🌱

Your Logan County Garden Planner — Free

A 22-page printable planner built for Logan 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 Logan 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.