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When to plant Echinacea (Purple Coneflower) in Solano County County,

Echinacea (Purple Coneflower) planted in Solano County County between January 26 and February 16 matures in 90 days — well before the December 3 first frost.

When to Plant Echinacea (Purple Coneflower) in Solano County, CA

Solano County, California Zone 9b June

June to-do list for Solano County, California

Here's what deserves your attention in Solano County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 9
Avg. first frost December 3
Soil temp (4") 85°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
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  • First harvests: echinacea (purple coneflower)

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Echinacea purpurea (Purple Coneflower) is a long-lived native prairie perennial and one of the most valuable pollinator plants in North American gardens. Its distinctive daisy-like blooms — swept-back lavender-pink petals surrounding a spiny orange-brown cone — attract bees, butterflies, and goldfinches from summer into fall. Drought-tolerant once established, adaptable to average soils, and impressively long-lived; mature clumps bloom reliably for decades.

Solano County, California is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.

At an elevation of 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Echinacea (Purple Coneflower) may need afternoon shade and extra watering during peak heat.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Solano County, CA (Zone 9b) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3
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Solano County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Echinacea (Purple Coneflower) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (109 days to spare)
Start indoors: Nov 30 Transplant: Jan 11 🌸 Bloom: Mar 22 – Aug 9
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Dec 15 Transplant: Jan 26 🌸 Bloom: Apr 6 – Aug 24
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Jan 16 Transplant: Feb 27 🌸 Bloom: May 8 – Sep 25

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 Solano County

How your county's soil matches Echinacea (Purple Coneflower)'s growing requirements.

Soil pH

Your soil pH (6.8–7.3) is more alkaline than Echinacea (Purple Coneflower) prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Solano County is excellent for Echinacea (Purple Coneflower) — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Echinacea (Purple Coneflower).

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Echinacea (Purple Coneflower).

How to Plant Echinacea (Purple Coneflower)

0.3"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Echinacea (Purple Coneflower)

5
successive plantings in your 297-day season

Sow every 8 weeks. Last sowing by Sep 04 to harvest before frost.

Echinacea (Purple Coneflower) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 257 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Echinacea (Purple Coneflower)

Echinacea (Purple Coneflower) needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Echinacea (Purple Coneflower) Needs Rainfall You Supplement Action
Jan 8.9" 0" ❄️ Dormant
Feb 2.2" 8.4" 0" ✅ Rainfall sufficient
Mar 2.2" 6.6" 0" ✅ Rainfall sufficient
Apr 2.2" 2.7" 0" ✅ Rainfall sufficient
May 2.2" 1" 1.2" 🚿 Regular watering
Jun 2.2" 0.2" 2" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.4" 1.8" 🚿 Regular watering
Oct 2.2" 1.9" 0.3" 💧 Light watering
Nov 2.2" 3.3" 0" ✅ Rainfall sufficient
Dec 2.2" 7.1" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Solano County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Echinacea (Purple Coneflower) 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.

Echinacea (Purple Coneflower) needs ~1,700 GDD — county provides 6,332 GDD Excellent fit

Echinacea (Purple Coneflower) Planting Timeline — Solano County, CA

Echinacea (Purple Coneflower) Planting Calendar

Activity When Date Range
Start Indoors December 15 Dec 15 – Dec 29
Transplant Outdoors January 26 Jan 26 – Feb 9
Direct Sow January 26 Jan 26 – Feb 16
Bloom April 6 Apr 6 – Aug 24

Plant 0.3" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

297 days in Solano County

Growing Tips for Echinacea (Purple Coneflower) in Solano County

Direct sow Echinacea (Purple Coneflower) outdoors after February 09 in Solano County when soil has warmed and frost danger has passed.

Common pests for Echinacea (Purple Coneflower) in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8–10 weeks before last frost or direct-sow in fall for natural cold stratification. Seeds require 4–8 weeks of cold moist stratification (or fall sowing) for best germination. Transplant when night temps stay above 50°F. Full sun is essential for heavy bloom. Avoid over-fertilizing — lean soil produces more compact, floriferous plants. Deadhead for continuous bloom but leave some cones standing in fall for goldfinch seed harvest. Year 2+ plants bloom most heavily; first-year transplants may produce limited flowers. Divide congested clumps every 3–4 years in early spring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Echinacea (Purple Coneflower) in Solano County, CA?

Solano County is in Zone 9b with an average last frost of February 9. Plan your Echinacea (Purple Coneflower) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Solano County, CA?

Solano County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.

When should I plant Echinacea (Purple Coneflower) in Solano County, ?

In Solano County, , plant Echinacea (Purple Coneflower) after the last frost (around February 9) and before the first frost (around December 3). Best results when soil holds above 50°F.

What growing zone is Solano County, for Echinacea (Purple Coneflower)?

Solano County sits in USDA Zone 9b. Echinacea (Purple Coneflower) grows reliably in zones 3a through 9b, so it's a good fit here.

Can Echinacea (Purple Coneflower) grow in Solano County's climate?

Yes — Echinacea (Purple Coneflower) grows well in Solano County's temperate climate. Solano County averages a 298-day frost-free season, with last frost around February 9 and first frost around December 3.

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Your Solano County Garden Planner — Free

A 22-page printable planner built for Solano 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 Solano County, CA. 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.