Blog

When to plant Lobelia in Stevens County, KS

Stevens County's 179-day season only supports one Lobelia planting per year. Sow between April 6 and April 20 for the best chance at full maturity before October 16.

When to Plant Lobelia in Stevens County, KS

Stevens County, Kansas Zone 6b July

What to do in July

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

Avg. last frost April 20
Avg. first frost October 16
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 14.3 hrs
  1. Start harvesting lobelia

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

August prep starts now
  • 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.

Stevens County, Kansas is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 16, giving you a growing season of approximately 179 days.

At an elevation of 1,123 feet, Stevens County receives approximately 31.9 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
Stevens County, KS (Zone 6b) Moderate season
179 days
Last Spring Frost April 20
179 growing days
First Fall Frost October 16

Stevens County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Feb 11 Transplant: Apr 1 🌸 Bloom: May 27 – Aug 19
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Feb 16 Transplant: Apr 6 🌸 Bloom: Jun 1 – Aug 24
Safe Start (90%) ✓ Fits season (54 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 Stevens County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Lobelia.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 179-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
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,054 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 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 2.5" 1.8" 💧 Light watering
Jul 4.3" 2.7" 1.6" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stevens 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 2,595 GDD Excellent fit

Lobelia Planting Timeline — Stevens County, KS

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 6 Apr 6 – Apr 20
Bloom June 1 Jun 1 – Aug 24

· 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 6b

📆 Growing Season

179 days in Stevens County

Growing Tips for Lobelia in Stevens County

Direct sow Lobelia outdoors after April 20 in Stevens 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 Stevens County, KS?

Stevens County is in Zone 6b with an average last frost of April 20. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stevens County, KS?

Stevens County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 16.

When should I plant Lobelia in Stevens County, KS?

In Stevens County, KS, plant Lobelia after the last frost (around April 20) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Stevens County, KS for Lobelia?

Stevens 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 Stevens County's climate?

Yes — Lobelia grows well in Stevens County's temperate climate. Stevens County averages a 179-day frost-free season, with last frost around April 20 and first frost around October 16.

🌱

Your Stevens County Garden Planner — Free

A 22-page printable planner built for Stevens 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 Stevens County, KS. Local conditions may vary. Last updated: July 2026.

Sources & credits

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