When to plant Feverfew in O'Brien County, IA
Plant Feverfew in O'Brien County during the brief May 8–May 22 window. With 157 frost-free days, fall plantings can't mature before October 5.
When to Plant Feverfew in O'Brien County, IA
Top priorities for O'Brien County, Iowa gardeners in August
August rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in O'Brien County, Iowa.
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Basket week: feverfew
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Get ahead of September
- First harvests: feverfew
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.
O'Brien County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 5, giving you a growing season of approximately 157 days.
At an elevation of 658 feet, O'Brien County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Feverfew to ensure they mature before fall.
O'Brien County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.2
Drainage
Well Drained
Feverfew Planting Risk Windows
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 O'Brien County
How your county's soil matches Feverfew's growing requirements.
Soil pH
Your soil pH (5.8–7.2) overlaps with Feverfew's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in O'Brien County is excellent for Feverfew — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Feverfew will thrive.
How to Plant Feverfew
Feverfew Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 3.8" | 0" | ❄️ Dormant |
| May | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in O'Brien 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 Planting Timeline — O'Brien County, IA
Feverfew Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Harvest | August 7 | Aug 7 – Oct 23 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
157 days in O'Brien County
Growing Tips for Feverfew in O'Brien County
Direct sow Feverfew outdoors after May 01 in O'Brien 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.
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 →
Feverfew in Other Locations
Frequently Asked Questions
When should I plant Feverfew in O'Brien County, IA?
O'Brien County is in Zone 5a with an average last frost of May 1. Plan your Feverfew planting based on this frost date — see the calendar above for exact timing.
What planting zone is O'Brien County, IA?
O'Brien County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 5.
When should I plant Feverfew in O'Brien County, IA?
In O'Brien County, IA, plant Feverfew after the last frost (around May 1) and before the first frost (around October 5). Best results when soil holds above 50°F.
What growing zone is O'Brien County, IA for Feverfew?
O'Brien County sits in USDA Zone 5a. Feverfew grows reliably in zones 5a through 9b, so it's a good fit here.
Can Feverfew grow in O'Brien County's climate?
Yes — Feverfew grows well in O'Brien County's temperate climate. O'Brien County averages a 157-day frost-free season, with last frost around May 1 and first frost around October 5.
Your O'Brien County Garden Planner — Free
A 22-page printable planner built for O'Brien County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.