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When to Plant Lobelia in Greer County, OK

Greer County, Oklahoma Zone 7b June

Your June game plan for Greer County, Oklahoma

Your garden in Greer County, Oklahoma is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 6
Avg. first frost November 4
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. Start lobelia indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Bring in the lobelia

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to July
  • 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.

Greer County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is November 4, giving you a growing season of approximately 212 days.

At an elevation of 602 feet, Greer County receives approximately 34.5 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Lobelia during the growing season.

Annual Blooms in Spring Pollinator-friendly
Greer County, OK (Zone 7b) Long season
212 days
Last Spring Frost April 6
212 growing days
First Fall Frost November 4

Greer County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.4

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Start indoors: Jan 24 Transplant: Feb 28 🌸 Bloom: Apr 25 – Jul 4
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Feb 2 Transplant: Mar 9 🌸 Bloom: May 4 – Jul 13
Safe Start (90%) ✓ Fits season (120 days to spare)
Start indoors: Feb 11 Transplant: Mar 18 🌸 Bloom: May 13 – Jul 22

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 Greer County

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

Soil pH

Your soil pH (6.7–7.4) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Greer County is excellent for Lobelia — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Lobelia will thrive.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

3
successive plantings in your 212-day season

Sow every 8 weeks. Last sowing by Aug 16 to harvest before frost.

Lobelia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 717 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.9" 0" ✅ Rainfall sufficient
Jun 4.3" 5.9" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 4.3" 1.1" 3.2" 🚿 Regular watering
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Greer 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 ~1,425 GDD — county provides 4,028 GDD Excellent fit

Lobelia Planting Timeline — Greer County, OK

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 – Feb 16
Transplant Outdoors March 9 Mar 9 – Mar 23
Bloom May 4 May 4 – Jul 13

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Transplant Outdoors
April
May Bloom
June Bloom
July Bloom
August
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: too_alkaline

🗺️ USDA Zone

Zone 7b

📆 Growing Season

212 days in Greer County

Growing Tips for Lobelia in Greer County

Direct sow Lobelia outdoors after April 06 in Greer 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 Greer County, OK?

Greer County is in Zone 7b with an average last frost of April 6. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greer County, OK?

Greer County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is November 4.

🌱

Your Greer County Garden Planner — Free

A 22-page printable planner built for Greer County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Greer County, OK. 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.