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When to plant Echinacea (Purple Coneflower) in Phillipsville, CA

Phillipsville gardeners should plant Echinacea (Purple Coneflower) between February 13 and March 6 in spring. With Phillipsville's Zone 9b climate (last frost February 27), Echinacea (Purple Coneflower) needs 70–90 days to mature — plant by August 30 for a full harvest.

When to Plant Echinacea (Purple Coneflower) in Phillipsville, CA

Humboldt County, California Zone 9b August

August in Humboldt County, California — your action list

If you only do a handful of things in the garden this August, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 27
Avg. first frost November 28
Soil temp (4") 93°F
Watering Critical
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: echinacea (purple coneflower)

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to September
  • 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.

Phillipsville, California is in USDA Zone 9b. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 274 days.

At an elevation of 148 feet, Humboldt County receives approximately 22.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°F, providing good warmth for Echinacea (Purple Coneflower) during the growing season. Sandy soil warms quickly in spring — great for early planting — but Echinacea (Purple Coneflower) will need more frequent watering and organic matter to retain nutrients.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Phillipsville, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28

Phillipsville Soil Profile

Soil Type

Sandy Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Echinacea (Purple Coneflower) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Dec 19 Transplant: Jan 30 🌸 Bloom: Apr 10 – Aug 28
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Jan 2 Transplant: Feb 13 🌸 Bloom: Apr 24 – Sep 11
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Feb 5 Transplant: Mar 19 🌸 Bloom: May 28 – Oct 15

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 Phillipsville

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

Soil pH

Your soil pH (6.2–6.8) is within Echinacea (Purple Coneflower)'s preferred range (6.0–7.0).

Soil Texture

Sandy soil in Humboldt County warms quickly in spring but drains fast. Echinacea (Purple Coneflower) will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.3%). 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)

4
successive plantings in your 274-day season

Sow every 8 weeks. Last sowing by Aug 30 to harvest before frost.

Echinacea (Purple Coneflower) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 398 gal / 100 sq ft

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 4.8" 0" ❄️ Dormant
Feb 2.2" 5" 0" ✅ Rainfall sufficient
Mar 2.2" 3.3" 0" ✅ Rainfall sufficient
Apr 2.2" 1.7" 0.5" 💧 Light watering
May 2.2" 0.5" 1.7" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.3" 1.9" 🚿 Regular watering
Oct 2.2" 0.8" 1.4" 🚿 Regular watering
Nov 2.2" 1.9" 0.3" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Humboldt 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 ~1,220 GDD — county provides 4,193 GDD Excellent fit

Echinacea (Purple Coneflower) Planting Timeline — Phillipsville, CA

Echinacea (Purple Coneflower) Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 – Jan 16
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow February 13 Feb 13 – Mar 6
Bloom April 24 Apr 24 – Sep 11

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

Month-by-Month Timeline

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

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: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Humboldt County

Growing Tips for Echinacea (Purple Coneflower) in Phillipsville

Direct sow Echinacea (Purple Coneflower) outdoors after February 27 in Humboldt County when soil has warmed and frost danger has passed.

Sandy soil in Humboldt County dries quickly — mulch Echinacea (Purple Coneflower) with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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

Humboldt County receives only 22" of rain annually. Echinacea (Purple Coneflower) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 →

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

In Phillipsville, CA, plant Echinacea (Purple Coneflower) after the last frost (around February 27) and before the first frost (around November 28). Best results when soil holds above 50°F.

What growing zone is Phillipsville, CA for Echinacea (Purple Coneflower)?

Phillipsville 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 Phillipsville's climate?

Yes — Echinacea (Purple Coneflower) grows well in Phillipsville's temperate climate. Phillipsville averages a 275-day frost-free season, with last frost around February 27 and first frost around November 28.

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Your Humboldt County Garden Planner — Free

A 22-page printable planner built for Humboldt 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 Humboldt County, CA. Local conditions may vary. Last updated: August 2026.