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When to plant Lobelia in Marion County, FL

In Marion County, Lobelia is a single-season spring crop — there's no second fall window. Plant December 21–January 4 for an 70–80-day harvest, finishing well before the December 1 first frost.

When to Plant Lobelia in Marion County, FL

Marion County, Florida Zone 9a June

Your June gardening checklist

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

Avg. last frost February 15
Avg. first frost December 1
Soil temp (4") 87°F
Watering Low
Pest pressure High
Daylight 13.9 hrs

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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.

Marion County, Florida is in USDA Zone 9a. The average last spring frost is February 15 and the first fall frost is December 1, giving you a growing season of approximately 289 days.

At an elevation of 244 feet, Marion County receives approximately 54.1 inches of rainfall annually with predominantly sand soil. Summer highs average 97°F, so Lobelia may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lobelia will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lobelia root diseases.

Annual Blooms in Spring Pollinator-friendly
Marion County, FL (Zone 9a) Year-round
289 days
Last Spring Frost February 15
289 growing days
First Fall Frost December 1

Marion County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.9

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (262 days to spare)
Start indoors: Dec 12 Transplant: Dec 12 🌸 Bloom: Feb 6 – Mar 6
Recommended (50%) ✓ Fits season (261 days to spare)
Start indoors: Dec 21 Transplant: Dec 21 🌸 Bloom: Feb 15 – Mar 15
Safe Start (90%) ✓ Fits season (253 days to spare)
Start indoors: Jan 18 Transplant: Jan 18 🌸 Bloom: Mar 15 – Apr 12

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 Marion County

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

Soil pH

Your soil pH (4.8–5.9) is more acidic than Lobelia prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Marion County warms quickly in spring but drains fast. Lobelia will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Lobelia.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

4
successive plantings in your 289-day season

Sow every 8 weeks. Last sowing by Sep 12 to harvest before frost.

Lobelia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,333 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 2.2" 0" ❄️ Dormant
Feb 4.3" 2.7" 1.6" 💧 Light watering
Mar 4.3" 3.5" 0.8" 💧 Light watering
Apr 4.3" 2.2" 2.1" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 7.2" 0" ✅ Rainfall sufficient
Jul 4.3" 8.6" 0" ✅ Rainfall sufficient
Aug 4.3" 8.6" 0" ✅ Rainfall sufficient
Sep 4.3" 7.4" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 4.3" 2.1" 2.2" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Marion 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 ~1,706 GDD — county provides 6,597 GDD Excellent fit

Lobelia Planting Timeline — Marion County, FL

Lobelia Planting Calendar

Activity When Date Range
Start Indoors December 21 Dec 21 – Jan 4
Transplant Outdoors December 21 Dec 21 – Jan 4
Bloom February 15 Feb 15 – Mar 15

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors
February Bloom
March Bloom
April
May
June
July
August
September
October
November
December Start Indoors Transplant Outdoors

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: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

289 days in Marion County

Growing Tips for Lobelia in Marion County

Direct sow Lobelia outdoors after February 15 in Marion County when soil has warmed and frost danger has passed.

Sandy soil in Marion County dries quickly — mulch Lobelia with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Marion County, provide afternoon shade for Lobelia and water deeply in the morning.

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 Marion County, FL?

Marion County is in Zone 9a with an average last frost of February 15. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marion County, FL?

Marion County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 15 and first fall frost is December 1.

When should I plant Lobelia in Marion County, FL?

In Marion County, FL, plant Lobelia after the last frost (around February 15) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Marion County, FL for Lobelia?

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

Can Lobelia grow in Marion County's climate?

Yes — Lobelia grows well in Marion County's temperate climate. Marion County averages a 290-day frost-free season, with last frost around February 15 and first frost around December 1.

🌱

Your Marion County Garden Planner — Free

A 22-page printable planner built for Marion County (Zone 9a). 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 Marion County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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