Blog

When to plant Lobelia in Trego County County,

Plant Lobelia in Trego County County during the brief April 7–April 21 window. With 178 frost-free days, fall plantings can't mature before October 16.

When to Plant Lobelia in Trego County, KS

Trego County, Kansas Zone 6a June

Your June game plan for Trego County, Kansas

Welcome to June in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 21
Avg. first frost October 16
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Time to start lobelia inside

    These need a head start before your last frost (April 21). Sow into cells now so you're ready to transplant in a few weeks.

  2. It's harvest week for lobelia

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before July arrives, get these ready
  • 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.

Trego County, Kansas is in USDA Zone 6a. The average last spring frost is April 21 and the first fall frost is October 16, giving you a growing season of approximately 178 days.

At an elevation of 618 feet, Trego County receives approximately 30.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lobelia to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly
Trego County, KS (Zone 6a) Moderate season
178 days
Last Spring Frost April 21
178 growing days
First Fall Frost October 16

Trego County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Feb 12 Transplant: Apr 2 🌸 Bloom: May 28 – Aug 20
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 17 Transplant: Apr 7 🌸 Bloom: Jun 2 – Aug 25
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Mar 2 Transplant: Apr 20 🌸 Bloom: Jun 15 – Sep 7

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 Trego County

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

Soil pH

Your soil pH (6.6–7.8) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Lobelia will thrive.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 178-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
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 519 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" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2" 2.3" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Trego 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 ~975 GDD — county provides 2,314 GDD Excellent fit

Lobelia Planting Timeline — Trego County, KS

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 7 Apr 7 – Apr 21
Bloom June 2 Jun 2 – Aug 25

· 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 · 1-2 times/week

📅 Days to Maturity

70–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

178 days in Trego County

Growing Tips for Lobelia in Trego County

Direct sow Lobelia outdoors after April 21 in Trego 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 Trego County, KS?

Trego County is in Zone 6a with an average last frost of April 21. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Trego County, KS?

Trego County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 21 and first fall frost is October 16.

When should I plant Lobelia in Trego County County, ?

In Trego County County, , plant Lobelia after the last frost (around April 21) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Trego County County, for Lobelia?

Trego County 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 Trego County County's climate?

Yes — Lobelia grows well in Trego County County's temperate climate. Trego County County averages a 178-day frost-free season, with last frost around April 21 and first frost around October 16.

🌱

Your Trego County Garden Planner — Free

A 22-page printable planner built for Trego 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.

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 Trego 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.