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When to Plant Lobelia in Juab County, UT

Juab County, Utah Zone 6b June

June to-do list for Juab County, Utah

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

Avg. last frost May 19
Avg. first frost October 2
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 14.8 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.

Coming up in July — start thinking about
  • 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.

Juab County, Utah is in USDA Zone 6b. The average last spring frost is May 19 and the first fall frost is October 2, giving you a growing season of approximately 136 days.

At an elevation of 8,143 feet, Juab County receives approximately 23.3 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
Juab County, UT (Zone 6b) Short season
136 days
Last Spring Frost May 19
136 growing days
First Fall Frost October 2

Juab County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🌸 Bloom: Jun 23 – Sep 15
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Mar 17 Transplant: May 5 🌸 Bloom: Jun 30 – Sep 22
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Apr 7 Transplant: May 26 🌸 Bloom: Jul 21 – Oct 13

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 Juab County

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

Soil pH

Your soil pH (6.5–7.6) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 136-day season

Sow every 8 weeks. Last sowing by Jul 14 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 407 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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Juab 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 1,768 GDD Excellent fit

Lobelia Planting Timeline — Juab County, UT

Lobelia Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 5 May 5 – May 19
Bloom June 30 Jun 30 – Sep 22

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
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 6b

📆 Growing Season

136 days in Juab County

Growing Tips for Lobelia in Juab County

Direct sow Lobelia outdoors after May 19 in Juab County when soil has warmed and frost danger has passed.

Juab County receives only 23" 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 Juab County, UT?

Juab County is in Zone 6b with an average last frost of May 19. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Juab County, UT?

Juab County, Utah is in USDA Hardiness Zone 6b. The average last spring frost is May 19 and first fall frost is October 2.

🌱

Your Juab County Garden Planner — Free

A 22-page printable planner built for Juab 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.

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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 Juab County, UT. 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.