Blog

When to plant Lobelia in Gray County County,

Plant Lobelia in Gray County County during the brief April 4–April 18 window. With 184 frost-free days, fall plantings can't mature before October 19.

When to Plant Lobelia in Gray County, KS

Gray County, Kansas Zone 6b June

Your June game plan for Gray County, Kansas

Your Gray County, Kansas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 18
Avg. first frost October 19
Soil temp (4") 73°F
Watering High
Pest pressure High
Daylight 14.6 hrs
  1. Get lobelia seeds going inside

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

  2. Start harvesting lobelia

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to July
  • First harvests: lobelia

Instant PDF download. No spam, unsubscribe any time.

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.

Gray County, Kansas is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 19, giving you a growing season of approximately 184 days.

At an elevation of 903 feet, Gray County receives approximately 30.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Lobelia during the growing season.

Annual Blooms in Spring Pollinator-friendly
Gray County, KS (Zone 6b) Moderate season
184 days
Last Spring Frost April 18
184 growing days
First Fall Frost October 19
Share this guide:

Gray County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Feb 10 Transplant: Mar 31 🌸 Bloom: May 26 – Aug 18
Recommended (50%) ✓ Fits season (58 days to spare)
Start indoors: Feb 14 Transplant: Apr 4 🌸 Bloom: May 30 – Aug 22
Safe Start (90%) ✓ Fits season (59 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 Gray County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

3
successive plantings in your 184-day season

Sow every 8 weeks. Last sowing by Jul 31 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 593 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 2" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 2.9" 1.4" 💧 Light watering
Aug 4.3" 3.1" 1.2" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 1.8" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Gray 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 ~1,088 GDD — county provides 2,668 GDD Excellent fit

Lobelia Planting Timeline — Gray County, KS

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors April 4 Apr 4 – Apr 18
Bloom May 30 May 30 – Aug 22

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

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 6b

📆 Growing Season

184 days in Gray County

Growing Tips for Lobelia in Gray County

Direct sow Lobelia outdoors after April 18 in Gray 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 Gray County, KS?

Gray County is in Zone 6b with an average last frost of April 18. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gray County, KS?

Gray County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 19.

When should I plant Lobelia in Gray County County, ?

In Gray County County, , plant Lobelia after the last frost (around April 18) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Gray County County, for Lobelia?

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

Can Lobelia grow in Gray County County's climate?

Yes — Lobelia grows well in Gray County County's temperate climate. Gray County County averages a 184-day frost-free season, with last frost around April 18 and first frost around October 19.

🌱

Your Gray County Garden Planner — Free

A 22-page printable planner built for Gray County (Zone 6b). 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 Gray County, KS. 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.