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When to plant Lobelia in Fulton County, IL

In Fulton County, Lobelia is a spring-only crop. Plant April 6–April 20 once soil hits 50°F.

When to Plant Lobelia in Fulton County, IL

Fulton County, Illinois Zone 6a July

This month in Fulton County, Illinois

July is a pivotal month for Fulton County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 20
Avg. first frost October 16
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. It's harvest week for lobelia

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of August
  • First harvests: lobelia

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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.

Fulton County, Illinois is in USDA Zone 6a. The average last spring frost is April 20 and the first fall frost is October 16, giving you a growing season of approximately 179 days.

At an elevation of 1,162 feet, Fulton County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Lobelia to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly
Fulton County, IL (Zone 6a) Moderate season
179 days
Last Spring Frost April 20
179 growing days
First Fall Frost October 16

Fulton County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Feb 10 Transplant: Mar 31 🌸 Bloom: May 26 – Aug 18
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Feb 16 Transplant: Apr 6 🌸 Bloom: Jun 1 – Aug 24
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Feb 28 Transplant: Apr 18 🌸 Bloom: Jun 13 – Sep 5

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 Fulton County

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

Soil pH

Your soil pH (6.1–6.7) is within Lobelia's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Fulton 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

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 179-day season

Sow every 8 weeks. Last sowing by Jul 28 to harvest before frost.

Lobelia 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 117 gal / 100 sq ft

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 1.8" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Fulton 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 needs ~919 GDD — county provides 2,192 GDD Excellent fit

Lobelia Planting Timeline — Fulton County, IL

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 6 Apr 6 – Apr 20
Bloom June 1 Jun 1 – Aug 24

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

179 days in Fulton County

Growing Tips for Lobelia in Fulton County

Direct sow Lobelia outdoors after April 20 in Fulton 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 →

Frequently Asked Questions

When should I plant Lobelia in Fulton County, IL?

Fulton County is in Zone 6a with an average last frost of April 20. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fulton County, IL?

Fulton County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 20 and first fall frost is October 16.

When should I plant Lobelia in Fulton County, IL?

In Fulton County, IL, plant Lobelia after the last frost (around April 20) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Fulton County, IL for Lobelia?

Fulton County sits in USDA Zone 6a. Lobelia grows reliably in zones 3a through 9b, so it's a good fit here.

Can Lobelia grow in Fulton County's climate?

Yes — Lobelia grows well in Fulton County's temperate climate. Fulton County averages a 179-day frost-free season, with last frost around April 20 and first frost around October 16.

🌱

Your Fulton County Garden Planner — Free

A 22-page printable planner built for Fulton County (Zone 6a). 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 Fulton County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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