When to plant Phlox in Marshall County County,
The best window to plant Phlox in Marshall County County, is April 10–May 1, when soil warms to 50°F. Last frost typically hits April 3; first frost November 1.
When to Plant Phlox in Marshall County, KY
Top priorities for Marshall County, Kentucky gardeners in June
Your garden in Marshall County, Kentucky is working on a schedule, even when you're not. Here's where you should be this June.
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Start phlox indoors
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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Start harvesting phlox
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
July will be here before you know it — start on
- First harvests: phlox
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.
Marshall County, Kentucky is in USDA Zone 7a. The average last spring frost is April 3 and the first fall frost is November 1, giving you a growing season of approximately 212 days.
At an elevation of 1,550 feet, Marshall County receives approximately 42.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Phlox during the growing season.
Marshall County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-7.1
Drainage
Well Drained
Phlox Planting Risk Windows
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 Marshall 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 Marshall County is excellent for Phlox — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Phlox.
How to Plant Phlox
Succession Planting Phlox
Sow every 9.1 weeks. Last sowing by Jul 14 to harvest before frost.
Phlox Water Budget
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 | — | 3.6" | 0" | ❄️ Dormant |
| Feb | — | 4" | 0" | ❄️ Dormant |
| Mar | — | 4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| May | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Jun | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jul | 4.3" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4" | 0.3" | 💧 Light watering |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | 4.3" | 3" | 1.3" | 💧 Light watering |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Marshall 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 Planting Timeline — Marshall County, KY
Phlox Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 30 | Jan 30 – Feb 13 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Direct Sow | April 10 | Apr 10 – May 1 |
| Bloom | June 19 | Jun 19 – Sep 11 |
Plant 0.3" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Only during dry spells
📅 Days to Maturity
80–110 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
212 days in Marshall County
Growing Tips for Phlox in Marshall County
Direct sow Phlox outdoors after April 03 in Marshall 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 →
Phlox in Other Locations
Frequently Asked Questions
When should I plant Phlox in Marshall County, KY?
Marshall County is in Zone 7a with an average last frost of April 3. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, KY?
Marshall County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 3 and first fall frost is November 1.
When should I plant Phlox in Marshall County, ?
In Marshall County, , plant Phlox after the last frost (around April 3) and before the first frost (around November 1). Best results when soil holds above 50°F.
What growing zone is Marshall County, for Phlox?
Marshall 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 Marshall County's climate?
Yes — Phlox grows well in Marshall County's temperate climate. Marshall County averages a 212-day frost-free season, with last frost around April 3 and first frost around November 1.
Your Marshall County Garden Planner — Free
A 22-page printable planner built for Marshall 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.