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When to plant Lobelia in Sutter County, CA

Sutter County sits in cold Zone 9b. Plant Lobelia December 31–January 14 for the single annual harvest; the November 26 first frost closes the window.

When to Plant Lobelia in Sutter County, CA

Sutter County, California Zone 9b July

July to-do list for Sutter County, California

Welcome to July in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 4
Avg. first frost November 26
Soil temp (4") 93°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs

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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.

Sutter County, California is in USDA Zone 9b. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.

At an elevation of 484 feet, Sutter County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Lobelia during the growing season.

Annual Blooms in Spring Pollinator-friendly
Sutter County, CA (Zone 9b) Long season
267 days
Last Spring Frost March 4
267 growing days
First Fall Frost November 26

Sutter County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Lobelia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (258 days to spare)
Start indoors: Dec 13 Transplant: Dec 6 🌸 Bloom: Jan 31 – Feb 28
Recommended (50%) ✓ Fits season (246 days to spare)
Start indoors: Jan 7 Transplant: Dec 31 🌸 Bloom: Feb 25 – Mar 25
Safe Start (90%) ✓ Fits season (213 days to spare)
Start indoors: Mar 2 Transplant: Feb 23 🌸 Bloom: Apr 20 – May 18

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 Sutter County

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

Soil pH

Your soil pH (6.8–7.7) is more alkaline than Lobelia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Sutter 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 (2.4%). Annual compost additions will help Lobelia.

How to Plant Lobelia

6"
Between Plants
8"
Between Rows

Succession Planting Lobelia

4
successive plantings in your 267-day season

Sow every 8 weeks. Last sowing by Sep 07 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 2,747 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 4.6" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 4.3" 3.7" 0.6" 💧 Light watering
Apr 4.3" 1.4" 2.9" 🚿 Regular watering
May 4.3" 0.6" 3.7" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.9" 3.4" 🚿 Regular watering
Nov 4.3" 1.8" 2.5" 🚿 Regular watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Sutter 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 ~1,200 GDD — county provides 4,272 GDD Excellent fit

Lobelia Planting Timeline — Sutter County, CA

Lobelia Planting Calendar

Activity When Date Range
Start Indoors January 7 Jan 7 – Jan 21
Transplant Outdoors December 31 Dec 31 – Jan 14
Bloom February 25 Feb 25 – Mar 25

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

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 9b

📆 Growing Season

267 days in Sutter County

Growing Tips for Lobelia in Sutter County

Direct sow Lobelia outdoors after March 04 in Sutter County when soil has warmed and frost danger has passed.

Sutter County receives only 21" 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 Sutter County, CA?

Sutter County is in Zone 9b with an average last frost of March 4. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sutter County, CA?

Sutter County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 4 and first fall frost is November 26.

When should I plant Lobelia in Sutter County, CA?

In Sutter County, CA, plant Lobelia after the last frost (around March 4) and before the first frost (around November 26). Best results when soil holds above 50°F.

What growing zone is Sutter County, CA for Lobelia?

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

Can Lobelia grow in Sutter County's climate?

Yes — Lobelia grows well in Sutter County's temperate climate. Sutter County averages a 267-day frost-free season, with last frost around March 4 and first frost around November 26.

🌱

Your Sutter County Garden Planner — Free

A 22-page printable planner built for Sutter County (Zone 9b). 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 Sutter County, CA. 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.