When to plant Lobelia in Clinton County County,
Clinton County County sits in cold Zone 5a. Plant Lobelia April 10–April 24 for the single annual harvest; the October 16 first frost closes the window.
When to Plant Lobelia in Clinton County, IA
June to-do list for Clinton County, Iowa
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Clinton County, Iowa.
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Start lobelia indoors
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Basket week: lobelia
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Before July arrives, get these ready
- First harvests: lobelia
Lobelia (Lobelia erinus) is a cool-season annual prized for the intense cobalt blue that is rare among bedding flowers. It blooms most prolifically in spring and early summer but stalls or dies back during heat peaks above 90°F. In zones 3–7 it delivers a long display; in zones 8–9 it is best treated as a spring annual that fades by midsummer. Trailing types cascade beautifully from containers and window boxes.
Clinton County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.
At an elevation of 964 feet, Clinton County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Lobelia to ensure they mature before fall.
Clinton County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7.3
Drainage
Well Drained
Lobelia 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 Clinton County
How your county's soil matches Lobelia's growing requirements.
Soil pH
Your soil pH (6.3–7.3) overlaps with Lobelia's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Clinton County is excellent for Lobelia — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.0%) — Lobelia will thrive.
How to Plant Lobelia
Succession Planting Lobelia
Sow every 8 weeks. Last sowing by Jul 28 to harvest before frost.
Lobelia Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Lobelia
Lobelia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Lobelia Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| May | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4" | 0.3" | 💧 Light watering |
| Aug | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Clinton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lobelia 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.
Lobelia Planting Timeline — Clinton County, IA
Lobelia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 6 | Feb 6 – Feb 20 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Bloom | June 5 | Jun 5 – Aug 14 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
70–80 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
182 days in Clinton County
Growing Tips for Lobelia in Clinton County
Direct sow Lobelia outdoors after April 17 in Clinton County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors 10–12 weeks before last frost — seed is dust-fine and requires light to germinate; surface-sow and press gently. Keep at 65–70°F. Not reliably direct-sown. Transplant in cool weather, 2–4 weeks before last frost date is acceptable in zones 5+. Shear plants by one-third after the first bloom flush to encourage a second flush in fall. Provide afternoon shade in zones 7+ to extend bloom into summer.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Lobelia in Other Locations
Frequently Asked Questions
When should I plant Lobelia in Clinton County, IA?
Clinton County is in Zone 5a with an average last frost of April 17. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clinton County, IA?
Clinton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.
When should I plant Lobelia in Clinton County County, ?
In Clinton County County, , plant Lobelia after the last frost (around April 17) and before the first frost (around October 16). Best results when soil holds above 50°F.
What growing zone is Clinton County County, for Lobelia?
Clinton County County sits in USDA Zone 5a. Lobelia grows reliably in zones 3a through 9b, so it's a good fit here.
Can Lobelia grow in Clinton County County's climate?
Yes — Lobelia grows well in Clinton County County's temperate climate. Clinton County County averages a 182-day frost-free season, with last frost around April 17 and first frost around October 16.
Your Clinton County Garden Planner — Free
A 22-page printable planner built for Clinton County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.