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When to Plant Lobelia in Douglas County, NV

Douglas County, Nevada 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 May 12
Avg. first frost October 10
Soil temp (4") 63°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Fire up the seed-starting tray: lobelia

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Harvest lobelia as they ripen

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

Coming up in August — start thinking about
  • 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.

Douglas County, Nevada is in USDA Zone 6b. The average last spring frost is May 12 and the first fall frost is October 10, giving you a growing season of approximately 151 days.

At an elevation of 5,945 feet, Douglas County receives approximately 9.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Lobelia may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lobelia will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Lobelia successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Spring Pollinator-friendly
Douglas County, NV (Zone 6b) Moderate season
151 days
Last Spring Frost May 12
151 growing days
First Fall Frost October 10

Douglas County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.7

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Feb 27 Transplant: Apr 17 🌸 Bloom: Jun 12 – Sep 4
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🌸 Bloom: Jun 23 – Sep 15
Safe Start (90%) ✓ Fits season (16 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 Douglas County

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

Soil pH

Your soil pH (7.3–8.7) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Douglas County warms quickly in spring but drains fast. Lobelia will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Lobelia.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

2
successive plantings in your 151-day season

Sow every 8 weeks. Last sowing by Jul 22 to harvest before frost.

Lobelia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,670 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 0.7" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 0.5" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 4.3" 0.2" 4.1" 🚿 Regular watering
Jun 4.3" 0.4" 3.9" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 4.3" 0.9" 3.4" 🚿 Regular watering
Nov 0.5" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Douglas 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 ~1,762 GDD — county provides 3,548 GDD Excellent fit

Lobelia Planting Timeline — Douglas County, NV

Lobelia Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 28 Apr 28 – May 12
Bloom June 23 Jun 23 – Sep 15

· 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 · 2-3 times/week

📅 Days to Maturity

70–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

151 days in Douglas County

Growing Tips for Lobelia in Douglas County

Direct sow Lobelia outdoors after May 12 in Douglas County when soil has warmed and frost danger has passed.

Sandy soil in Douglas County dries quickly — mulch Lobelia with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 98°F in Douglas County, provide afternoon shade for Lobelia and water deeply in the morning.

Douglas County receives only 10" 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 Douglas County, NV?

Douglas County is in Zone 6b with an average last frost of May 12. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, NV?

Douglas County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 12 and first fall frost is October 10.

🌱

Your Douglas County Garden Planner — Free

A 22-page printable planner built for Douglas 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 Douglas County, NV. 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.