When to plant Lobelia in Lee County, IL
Lee County's short 175-day growing season means one Lobelia planting between April 15 and April 29. No fall crop in Zone 5b.
When to Plant Lobelia in Lee County, IL
Top priorities for Lee County, Illinois gardeners in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Lee County, Illinois.
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Basket week: lobelia
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Get ahead of July
- Starting indoors: lobelia
- 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.
Lee County, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.
At an elevation of 1,010 feet, Lee County receives approximately 33.6 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.
Lee County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.9
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 Lee County
How your county's soil matches Lobelia's growing requirements.
Soil pH
Your soil pH (6.3–6.9) is within Lobelia's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Lee County is excellent for Lobelia — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Lobelia.
Organic Matter
Organic matter is excellent (4.8%) — Lobelia will thrive.
How to Plant Lobelia
Succession Planting Lobelia
Sow every 8 weeks. Last sowing by Jul 26 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 3.3" | 1" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Lee 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 — Lee County, IL
Lobelia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 11 | Feb 11 – Feb 25 |
| Transplant Outdoors | April 15 | Apr 15 – Apr 29 |
| Bloom | June 10 | Jun 10 – Aug 26 |
· 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 · 1-2 times/week
📅 Days to Maturity
70–80 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Lee County
Growing Tips for Lobelia in Lee County
Direct sow Lobelia outdoors after April 22 in Lee 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 Lee County, IL?
Lee County is in Zone 5b with an average last frost of April 22. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lee County, IL?
Lee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 14.
When should I plant Lobelia in Lee County, IL?
In Lee County, IL, plant Lobelia after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.
What growing zone is Lee County, IL for Lobelia?
Lee County sits in USDA Zone 5b. Lobelia grows reliably in zones 3a through 9b, so it's a good fit here.
Can Lobelia grow in Lee County's climate?
Yes — Lobelia grows well in Lee County's temperate climate. Lee County averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.
Your Lee County Garden Planner — Free
A 22-page printable planner built for Lee County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.