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When to Plant Feverfew in Humboldt County, CA

Humboldt County, California Zone 9b May

This month in Humboldt County, California

Each item below is timed to Humboldt County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 27
Avg. first frost November 28
Soil temp (4") 74°F
Watering Critical
Pest pressure High
Daylight 14.3 hrs
Coming up in June — start thinking about
  • First harvests: feverfew

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Feverfew is a bushy perennial herb with small daisy-like flowers and aromatic leaves. It has been used traditionally for headache relief and is a cheerful garden plant.

Humboldt County, 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 Feverfew during the growing season. Sandy soil warms quickly in spring — great for early planting — but Feverfew will need more frequent watering and organic matter to retain nutrients.

Humboldt County, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Transplant: Feb 20 🍅 Harvest: May 22 – Aug 7
Recommended (50%) ✓ Fits season (99 days to spare)
Transplant: Mar 6 🍅 Harvest: Jun 5 – Aug 21
Safe Start (90%) ✓ Fits season (85 days to spare)
Transplant: Apr 9 🍅 Harvest: Jul 9 – Sep 24

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 Humboldt County

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

Soil pH

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

Soil Texture

Sandy soil in Humboldt County warms quickly in spring but drains fast. Feverfew 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 Feverfew.

How to Plant Feverfew

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant 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 Feverfew

Feverfew 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 Feverfew 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.

Feverfew 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.

Feverfew needs ~1,601 GDD — county provides 4,193 GDD Excellent fit

Feverfew Planting Timeline — Humboldt County, CA

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors March 6 Mar 6 – Mar 20
Harvest June 5 Jun 5 – Aug 21

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April
May
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Humboldt County

Growing Tips for Feverfew in Humboldt County

Direct sow Feverfew outdoors after February 27 in Humboldt County when soil has warmed and frost danger has passed.

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

Common pests for Feverfew 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. Feverfew needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow on the soil surface. Deadhead regularly to prevent aggressive self-seeding. Divide clumps every 2-3 years to maintain vigor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Feverfew in Humboldt County, CA?

Humboldt County is in Zone 9b with an average last frost of February 27. Plan your Feverfew planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, CA?

Humboldt County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 27 and first fall frost is November 28.

🌱

Your Humboldt County Garden Planner — Free

A 24-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: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.