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When to plant Lobelia in Winneshiek County County,

Plant Lobelia in Winneshiek County County during the brief April 26–May 10 window. With 156 frost-free days, fall plantings can't mature before October 6.

When to Plant Lobelia in Winneshiek County, IA

Winneshiek County, Iowa Zone 5a June

This month in Winneshiek County, Iowa

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 3
Avg. first frost October 6
Soil temp (4") 63°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
  1. Pick lobelia

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

Looking ahead to July
  • Starting indoors: lobelia
  • 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.

Winneshiek County, Iowa is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 6, giving you a growing season of approximately 156 days.

At an elevation of 1,360 feet, Winneshiek County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Lobelia to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly
Winneshiek County, IA (Zone 5a) Moderate season
156 days
Last Spring Frost May 3
156 growing days
First Fall Frost October 6

Winneshiek County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🌸 Bloom: Jun 14 – Aug 23
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🌸 Bloom: Jun 21 – Aug 30
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Mar 7 Transplant: May 9 🌸 Bloom: Jul 4 – Sep 12

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 Winneshiek County

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

Soil pH

Your soil pH (5.9–6.8) overlaps with Lobelia's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Lobelia will thrive.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 156-day season

Sow every 8 weeks. Last sowing by Jul 18 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 195 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Winneshiek 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 ~750 GDD — county provides 1,560 GDD Excellent fit

Lobelia Planting Timeline — Winneshiek County, IA

Lobelia Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors April 26 Apr 26 – May 10
Bloom June 21 Jun 21 – Aug 30

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

156 days in Winneshiek County

Growing Tips for Lobelia in Winneshiek County

Direct sow Lobelia outdoors after May 03 in Winneshiek 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 Winneshiek County, IA?

Winneshiek County is in Zone 5a with an average last frost of May 3. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winneshiek County, IA?

Winneshiek County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 6.

When should I plant Lobelia in Winneshiek County County, ?

In Winneshiek County County, , plant Lobelia after the last frost (around May 3) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Winneshiek County County, for Lobelia?

Winneshiek County County sits in USDA Zone 5a. Lobelia grows reliably in zones 3a through 9b, so it's a good fit here.

Can Lobelia grow in Winneshiek County County's climate?

Yes — Lobelia grows well in Winneshiek County County's temperate climate. Winneshiek County County averages a 156-day frost-free season, with last frost around May 3 and first frost around October 6.

🌱

Your Winneshiek County Garden Planner — Free

A 22-page printable planner built for Winneshiek County (Zone 5a). 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 Winneshiek County, IA. 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.