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When to Plant Feverfew in Broomfield County, CO

Broomfield County, Colorado Zone 6a May

May in the garden — Broomfield County, Colorado

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Broomfield County, Colorado.

Avg. last frost May 14
Avg. first frost September 26
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Get feverfew in the ground

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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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.

Broomfield County, Colorado is in USDA Zone 6a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 7,037 feet, Broomfield County receives approximately 13.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Feverfew during the growing season. With low rainfall, drip irrigation is essential for growing Feverfew successfully. Mulch heavily to conserve soil moisture.

Broomfield County, CO (Zone 6a) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26
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Broomfield County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 10 🍅 Harvest: Aug 9 – Oct 25
Recommended (50%) ✗ May not fit
Transplant: May 21 🍅 Harvest: Aug 20 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Sep 16 – Dec 2

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 Broomfield County

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

Soil pH

Your soil pH (6.2–8.2) is more alkaline than Feverfew prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Broomfield County is excellent for Feverfew — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). 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
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 97 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.9" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 2.2" 1.7" 0.5" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.6" 0.6" 💧 Light watering
Sep 2.2" 1.1" 1.1" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Broomfield 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 2,058 GDD Good fit

Feverfew Planting Timeline — Broomfield County, CO

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors May 21 May 21 – Jun 4
Harvest August 20 Aug 20 – Nov 5

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6a

📆 Growing Season

135 days in Broomfield County

Growing Tips for Feverfew in Broomfield County

Direct sow Feverfew outdoors after May 14 in Broomfield County when soil has warmed and frost danger has passed.

Common pests for Feverfew in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Broomfield County receives only 14" 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 Broomfield County, CO?

Broomfield County is in Zone 6a with an average last frost of May 14. Plan your Feverfew planting based on this frost date — see the calendar above for exact timing.

What planting zone is Broomfield County, CO?

Broomfield County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.

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Your Broomfield County Garden Planner — Free

A 24-page printable planner built for Broomfield County (Zone 6a). 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 Broomfield County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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