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When to plant Phlox in Hardin County County,

Plant Phlox in Hardin County County after April 4; the prime window is April 11–May 2.

When to Plant Phlox in Hardin County, KY

Hardin County, Kentucky Zone 7a June

June to-do list for Hardin County, Kentucky

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 April 4
Avg. first frost November 1
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Start phlox indoors

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

  2. Harvest phlox as they ripen

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

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.

Hardin County, Kentucky is in USDA Zone 7a. The average last spring frost is April 4 and the first fall frost is November 1, giving you a growing season of approximately 211 days.

At an elevation of 1,464 feet, Hardin County receives approximately 48.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Phlox during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Hardin County, KY (Zone 7a) Long season
211 days
Last Spring Frost April 4
211 growing days
First Fall Frost November 1

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Jan 25 Transplant: Apr 5 🌸 Bloom: Jun 14 – Sep 6
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Jan 31 Transplant: Apr 11 🌸 Bloom: Jun 20 – Sep 12
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🌸 Bloom: Jul 8 – Sep 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 Hardin County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Phlox.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Phlox.

How to Plant Phlox

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

Succession Planting Phlox

3
successive plantings in your 211-day season

Sow every 9.1 weeks. Last sowing by Jul 14 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.5" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 5.6" 0" ✅ Rainfall sufficient
Aug 4.3" 5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Hardin 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 ~1,449 GDD — county provides 3,217 GDD Excellent fit

Phlox Planting Timeline — Hardin County, KY

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 11 Apr 11 – May 2
Bloom June 20 Jun 20 – Sep 12

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

211 days in Hardin County

Growing Tips for Phlox in Hardin County

Direct sow Phlox outdoors after April 04 in Hardin 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 Hardin County, KY?

Hardin County is in Zone 7a with an average last frost of April 4. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, KY?

Hardin County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 4 and first fall frost is November 1.

When should I plant Phlox in Hardin County County, ?

In Hardin County County, , plant Phlox after the last frost (around April 4) and before the first frost (around November 1). Best results when soil holds above 50°F.

What growing zone is Hardin County County, for Phlox?

Hardin County County sits in USDA Zone 7a. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.

Can Phlox grow in Hardin County County's climate?

Yes — Phlox grows well in Hardin County County's temperate climate. Hardin County County averages a 211-day frost-free season, with last frost around April 4 and first frost around November 1.

🌱

Your Hardin County Garden Planner — Free

A 22-page printable planner built for Hardin County (Zone 7a). 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 Hardin County, KY. 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.