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When to Plant Lobelia in Chambers County, TX

Chambers County, Texas Zone 9b June

Your June planting checklist for Chambers County, Texas

Welcome to June in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 12
Avg. first frost December 6
Soil temp (4") 88°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.

Chambers County, Texas is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 6, giving you a growing season of approximately 297 days.

At an elevation of 1 feet, Chambers County receives approximately 66.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°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
Chambers County, TX (Zone 9b) Year-round
297 days
Last Spring Frost February 12
297 growing days
First Fall Frost December 6

Chambers County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (287 days to spare)
Start indoors: Nov 29 Transplant: Nov 22 🌸 Bloom: Jan 17 – Feb 14
Recommended (50%) ✓ Fits season (276 days to spare)
Start indoors: Dec 18 Transplant: Dec 11 🌸 Bloom: Feb 5 – Mar 5
Safe Start (90%) ✓ Fits season (268 days to spare)
Start indoors: Jan 9 Transplant: Jan 2 🌸 Bloom: Feb 27 – Mar 27

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 Chambers County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Lobelia prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

5
successive plantings in your 297-day season

Sow every 8 weeks. Last sowing by Sep 17 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 181 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 1.4" 0" ❄️ Dormant
Feb 4.3" 2.3" 2" 💧 Light watering
Mar 4.3" 3.9" 0.4" 💧 Light watering
Apr 4.3" 6.6" 0" ✅ Rainfall sufficient
May 4.3" 10" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 8.5" 0" ✅ Rainfall sufficient
Aug 4.3" 7.2" 0" ✅ Rainfall sufficient
Sep 4.3" 6.4" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 4.3" 1.8" 2.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Chambers 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 ~1,819 GDD — county provides 7,226 GDD Excellent fit

Lobelia Planting Timeline — Chambers County, TX

Lobelia Planting Calendar

Activity When Date Range
Start Indoors December 18 Dec 18 – Jan 1
Transplant Outdoors December 11 Dec 11 – Dec 25
Bloom February 5 Feb 5 – Mar 5

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
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 · Only during dry spells

📅 Days to Maturity

70–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

297 days in Chambers County

Growing Tips for Lobelia in Chambers County

Direct sow Lobelia outdoors after February 12 in Chambers County when soil has warmed and frost danger has passed.

Sandy soil in Chambers 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 99°F in Chambers 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 Chambers County, TX?

Chambers County is in Zone 9b with an average last frost of February 12. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chambers County, TX?

Chambers County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 12 and first fall frost is December 6.

🌱

Your Chambers County Garden Planner — Free

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.