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When to plant Lobelia in Minidoka County County,

Minidoka County County sits in cold Zone 6a. Plant Lobelia April 26–May 10 for the single annual harvest; the October 3 first frost closes the window.

When to Plant Lobelia in Minidoka County, ID

Minidoka County, Idaho Zone 6a June

June in Minidoka County, Idaho — your action list

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 10
Avg. first frost October 3
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 15.1 hrs
  1. Pick lobelia

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong July, finish these tasks
  • 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.

Minidoka County, Idaho is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is October 3, giving you a growing season of approximately 146 days.

At an elevation of 5,990 feet, Minidoka County receives approximately 22.3 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
Minidoka County, ID (Zone 6a) Short season
146 days
Last Spring Frost May 10
146 growing days
First Fall Frost October 3

Minidoka 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 (22 days to spare)
Start indoors: Feb 27 Transplant: Apr 17 🌸 Bloom: Jun 12 – Sep 4
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Mar 8 Transplant: Apr 26 🌸 Bloom: Jun 21 – Sep 13
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Apr 4 Transplant: May 23 🌸 Bloom: Jul 18 – Oct 10

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 Minidoka 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 Minidoka County is excellent for Lobelia — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 146-day season

Sow every 8 weeks. Last sowing by Jul 15 to harvest before frost.

Lobelia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 559 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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Minidoka 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 2,117 GDD Excellent fit

Lobelia Planting Timeline — Minidoka County, ID

Lobelia Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors April 26 Apr 26 – May 10
Bloom June 21 Jun 21 – Sep 13

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

146 days in Minidoka County

Growing Tips for Lobelia in Minidoka County

Direct sow Lobelia outdoors after May 10 in Minidoka County when soil has warmed and frost danger has passed.

Minidoka County receives only 22" of rain annually. Lobelia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Minidoka County, ID?

Minidoka County is in Zone 6a with an average last frost of May 10. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Minidoka County, ID?

Minidoka County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is October 3.

When should I plant Lobelia in Minidoka County County, ?

In Minidoka County County, , plant Lobelia after the last frost (around May 10) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Minidoka County County, for Lobelia?

Minidoka 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 Minidoka County County's climate?

Yes — Lobelia grows well in Minidoka County County's temperate climate. Minidoka County County averages a 146-day frost-free season, with last frost around May 10 and first frost around October 3.

🌱

Your Minidoka County Garden Planner — Free

A 22-page printable planner built for Minidoka 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.

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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 Minidoka County, ID. 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.