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When to plant Phlox in Kent County County,

Kent County County's spring Phlox window runs April 9 through April 30. most warm-season crops establish quickly once soil holds above 60°F.

When to Plant Phlox in Kent County, DE

Kent County, Delaware Zone 7b June

Kent County, Delaware gardeners: here's your June plan

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

Avg. last frost April 2
Avg. first frost November 4
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Fire up the seed-starting tray: phlox

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Pick phlox

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Get ahead of 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.

Kent County, Delaware is in USDA Zone 7b. The average last spring frost is April 2 and the first fall frost is November 4, giving you a growing season of approximately 216 days.

At an elevation of 128 feet, Kent County receives approximately 47.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Phlox during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Kent County, DE (Zone 7b) Long season
216 days
Last Spring Frost April 2
216 growing days
First Fall Frost November 4
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Kent County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Jan 24 Transplant: Apr 4 🌸 Bloom: Jun 13 – Sep 5
Recommended (50%) ✓ Fits season (55 days to spare)
Start indoors: Jan 29 Transplant: Apr 9 🌸 Bloom: Jun 18 – Sep 10
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Feb 14 Transplant: Apr 25 🌸 Bloom: Jul 4 – Sep 26

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 Kent County

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.2%). 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 216-day season

Sow every 9.1 weeks. Last sowing by Jul 17 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 132 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" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 5.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 4" 0.3" 💧 Light watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Kent 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 ~1,520 GDD — county provides 3,456 GDD Excellent fit

Phlox Planting Timeline — Kent County, DE

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow April 9 Apr 9 – Apr 30
Bloom June 18 Jun 18 – Sep 10

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
June Bloom
July Bloom
August Bloom
September Bloom
October
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 7b

📆 Growing Season

216 days in Kent County

Growing Tips for Phlox in Kent County

Direct sow Phlox outdoors after April 02 in Kent 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 Kent County, DE?

Kent County is in Zone 7b with an average last frost of April 2. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kent County, DE?

Kent County, Delaware is in USDA Hardiness Zone 7b. The average last spring frost is April 2 and first fall frost is November 4.

When should I plant Phlox in Kent County County, ?

In Kent County County, , plant Phlox after the last frost (around April 2) and before the first frost (around November 4). Best results when soil holds above 50°F.

What growing zone is Kent County County, for Phlox?

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

Can Phlox grow in Kent County County's climate?

Yes — Phlox grows well in Kent County County's temperate climate. Kent County County averages a 216-day frost-free season, with last frost around April 2 and first frost around November 4.

🌱

Your Kent County Garden Planner — Free

A 22-page printable planner built for Kent County (Zone 7b). 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 Kent County, DE. 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.