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When to Plant Feverfew in Mahaska County, IA

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.

Mahaska County, Iowa is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 9, giving you a growing season of approximately 165 days.

At an elevation of 511 feet, Mahaska County receives approximately 32.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Feverfew to ensure they mature before fall.

Mahaska County, IA (Zone 5a) Moderate season
165 days
Last Spring Frost April 27
165 growing days
First Fall Frost October 9

Mahaska County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 28 🍅 Harvest: Jul 28 – Oct 13
Recommended (50%) ✗ May not fit
Transplant: May 4 🍅 Harvest: Aug 3 – Oct 19
Safe Start (90%) ✗ May not fit
Transplant: May 21 🍅 Harvest: Aug 20 – Nov 5

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.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Feverfew needs ~1,286 GDD — county provides 2,021 GDD Excellent fit

Feverfew Planting Timeline โ€” Mahaska County, IA

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors May 4 May 4 โ€“ May 18
Harvest August 3 Aug 3 โ€“ Oct 19

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

165 days

Growing Tips for Mahaska County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Feverfew in Mahaska County, IA?

Mahaska County is in Zone 5a with an average last frost of April 27. Plan your Feverfew planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mahaska County, IA?

Mahaska County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 9.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mahaska County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Mahaska County, IA. Local conditions may vary. Last updated: April 2026.