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When to plant Phlox in Madison County County,

Plant Phlox in Madison County County from April 22 to May 13 in spring. Madison County County sits in USDA Zone 7a, with last frost around April 15 and first frost on October 24.

When to Plant Phlox in Madison County, KY

Madison County, Kentucky Zone 7a June

June in Madison County, Kentucky — your action list

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

Avg. last frost April 15
Avg. first frost October 24
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Sow phlox in trays indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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.

Madison County, Kentucky is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 24, giving you a growing season of approximately 192 days.

At an elevation of 3,082 feet, Madison County receives approximately 53.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Phlox during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Phlox root diseases.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Madison County, KY (Zone 7a) Moderate season
192 days
Last Spring Frost April 15
192 growing days
First Fall Frost October 24
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Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7.1

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Feb 4 Transplant: Apr 15 🌸 Bloom: Jun 24 – Sep 16
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🌸 Bloom: Jul 1 – Sep 23
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Feb 28 Transplant: May 9 🌸 Bloom: Jul 18 – Oct 10

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 Madison County

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

Soil pH

Your soil pH (5.5–7.1) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Madison 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 (2.6%). 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 192-day season

Sow every 9.1 weeks. Last sowing by Jul 06 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/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 4.3" 0" ❄️ Dormant
Feb 4.3" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.3" 4.3" 0" ✅ Rainfall sufficient
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 5.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.5" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.1" 0" ❄️ Dormant
Dec 4.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 2,928 GDD Excellent fit

Phlox Planting Timeline — Madison County, KY

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 11 Feb 11 – Feb 25
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 22 Apr 22 – May 13
Bloom July 1 Jul 1 – Sep 23

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 Transplant Outdoors Direct Sow
June
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

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

192 days in Madison County

Growing Tips for Phlox in Madison County

Direct sow Phlox outdoors after April 15 in Madison 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 Madison County, KY?

Madison County is in Zone 7a with an average last frost of April 15. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, KY?

Madison County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 24.

When should I plant Phlox in Madison County County, ?

In Madison County County, , plant Phlox after the last frost (around April 15) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Madison County County, for Phlox?

Madison 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 Madison County County's climate?

Yes — Phlox grows well in Madison County County's temperate climate. Madison County County averages a 192-day frost-free season, with last frost around April 15 and first frost around October 24.

🌱

Your Madison County Garden Planner — Free

A 22-page printable planner built for Madison 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 Madison 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.