When to plant Feverfew in Onarga, IL
In Onarga, Feverfew is a spring-only crop. Plant April 25–May 9 once soil hits 50°F.
When to Plant Feverfew in Onarga, IL
What to do in July
A quick July briefing for Iroquois County, Illinois gardeners — what's urgent, what's next, and what can wait.
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Bring in the feverfew
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Get ahead of August
- 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.
Onarga, Illinois is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 13, giving you a growing season of approximately 178 days.
At an elevation of 1,345 feet, Iroquois County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Feverfew during the growing season.
Onarga Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
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 Onarga
How your county's soil matches Feverfew's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Feverfew's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Iroquois County is excellent for Feverfew — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Feverfew.
Organic Matter
Organic matter is excellent (4.5%) — Feverfew will thrive.
How to Plant Feverfew
Feverfew Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Iroquois 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 — Onarga, IL
Feverfew Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Harvest | July 25 | Jul 25 – Oct 10 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| 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 5b
📆 Growing Season
178 days in Iroquois County
Growing Tips for Feverfew in Onarga
Direct sow Feverfew outdoors after April 18 in Iroquois 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
When should I plant Feverfew in Onarga, IL?
In Onarga, IL, plant Feverfew after the last frost (around April 18) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Onarga, IL for Feverfew?
Onarga sits in USDA Zone 5b. Feverfew grows reliably in zones 5a through 9b, so it's a good fit here.
Can Feverfew grow in Onarga's climate?
Yes — Feverfew grows well in Onarga's temperate climate. Onarga averages a 178-day frost-free season, with last frost around April 18 and first frost around October 13.
Your Iroquois County Garden Planner — Free
A 22-page printable planner built for Iroquois County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.