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When to plant Phlox in Hart County, KY

Plant Phlox in Hart County from April 16 to May 7 in spring. Hart County sits in USDA Zone 7a, with last frost around April 9 and first frost on October 28.

When to Plant Phlox in Hart County, KY

Hart County, Kentucky Zone 7a July

Your July game plan for Hart County, Kentucky

Welcome to July in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 9
Avg. first frost October 28
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. Pick phlox

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in August — start thinking about
  • 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.

Hart County, Kentucky is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 28, giving you a growing season of approximately 202 days.

At an elevation of 3,611 feet, Hart County receives approximately 48.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Phlox during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Hart County, KY (Zone 7a) Long season
202 days
Last Spring Frost April 9
202 growing days
First Fall Frost October 28

Hart County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Jan 30 Transplant: Apr 10 🌸 Bloom: Jun 19 – Sep 11
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Feb 5 Transplant: Apr 16 🌸 Bloom: Jun 25 – Sep 17
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Feb 20 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 2

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 Hart County

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

Soil pH

Your soil pH (5.8–7.0) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Phlox.

How to Plant Phlox

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

Succession Planting Phlox

2
successive plantings in your 202-day season

Sow every 9.1 weeks. Last sowing by Jul 10 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

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 4" 0" ❄️ Dormant
Mar 5.1" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 4.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hart 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 ~1,734 GDD — county provides 3,686 GDD Excellent fit

Phlox Planting Timeline — Hart County, KY

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 16 Apr 16 – May 7
Bloom June 25 Jun 25 – Sep 17

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

Month-by-Month Timeline

MonthActivities
January
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

202 days in Hart County

Growing Tips for Phlox in Hart County

Direct sow Phlox outdoors after April 09 in Hart 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 Hart County, KY?

Hart County is in Zone 7a with an average last frost of April 9. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hart County, KY?

Hart County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 28.

When should I plant Phlox in Hart County, KY?

In Hart County, KY, plant Phlox after the last frost (around April 9) and before the first frost (around October 28). Best results when soil holds above 50°F.

What growing zone is Hart County, KY for Phlox?

Hart 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 Hart County's climate?

Yes — Phlox grows well in Hart County's temperate climate. Hart County averages a 202-day frost-free season, with last frost around April 9 and first frost around October 28.

🌱

Your Hart County Garden Planner — Free

A 22-page printable planner built for Hart 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 Hart County, KY. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.