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When to plant Ageratum in Knox County County,
In Knox County County, plant Ageratum in spring between April 19 and May 10, once soil temps hold above 50°F. Knox County County's last frost averages April 19, so most warm-season crops establish quickly once soil holds above 60°F. For a fall crop, sow between and — roughly 75 days before the first frost on October 21.
When to Plant Ageratum in Knox County, KY
This month in Knox County, Kentucky
Your Knox County, Kentucky garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Collect ageratum at their peak
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Looking ahead to July
- First harvests: ageratum
Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.
Knox County, Kentucky is in USDA Zone 7a. The average last spring frost is April 19 and the first fall frost is October 21, giving you a growing season of approximately 185 days.
At an elevation of 2,802 feet, Knox County receives approximately 46.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.
Knox County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-7
Drainage
Well Drained
Ageratum 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 Knox County
How your county's soil matches Ageratum's growing requirements.
Soil pH
Your soil pH (5.3–7.0) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Knox County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Ageratum.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Ageratum.
How to Plant Ageratum
Succession Planting Ageratum
Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.
Ageratum Water Budget
Monthly Watering Guide for Ageratum
Ageratum needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Ageratum Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.3" | 0" | ❄️ Dormant |
| Feb | — | 4" | 0" | ❄️ Dormant |
| Mar | — | 4.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Jun | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jul | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Nov | — | 3.8" | 0" | ❄️ Dormant |
| Dec | — | 4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Knox County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Ageratum 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.
Ageratum Planting Timeline — Knox County, KY
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 8 | Mar 8 – Mar 22 |
| Transplant Outdoors | April 19 | Apr 19 – May 3 |
| Direct Sow | April 19 | Apr 19 – May 10 |
| Bloom | June 14 | Jun 14 – Oct 4 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
185 days in Knox County
Growing Tips for Ageratum in Knox County
Direct sow Ageratum outdoors after April 19 in Knox County when soil has warmed and frost danger has passed.
Common pests for Ageratum in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Ageratum in Other Locations
Frequently Asked Questions
When should I plant Ageratum in Knox County, KY?
Knox County is in Zone 7a with an average last frost of April 19. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Knox County, KY?
Knox County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 19 and first fall frost is October 21.
When should I plant Ageratum in Knox County, ?
In Knox County, , plant Ageratum after the last frost (around April 19) and before the first frost (around October 21). Best results when soil holds above 50°F.
What growing zone is Knox County, for Ageratum?
Knox County sits in USDA Zone 7a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.
Can Ageratum grow in Knox County's climate?
Yes — Ageratum grows well in Knox County's temperate climate. Knox County averages a 185-day frost-free season, with last frost around April 19 and first frost around October 21.
Your Knox County Garden Planner — Free
A 22-page printable planner built for Knox 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.