When to Plant Arugula in Iroquois County, IL
Your May gardening checklist
A quick May briefing for Iroquois County, Illinois gardeners — what's urgent, what's next, and what can wait.
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Fire up the seed-starting tray: arugula
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Basket week: arugula
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
June prep starts now
- First harvests: arugula
Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.
Iroquois County, 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 Arugula during the growing season.
Iroquois County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
Drainage
Well Drained
Plant 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 Iroquois County
How your county's soil matches Arugula's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Arugula's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Iroquois County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Arugula.
Organic Matter
Organic matter is excellent (4.5%) — Arugula will thrive.
How to Plant Arugula
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Arugula
Sow every 3.4 weeks. Last sowing by Aug 24 to harvest before frost.
For a dedicated fall crop, sow by Aug 04.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Arugula
Arugula needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Arugula Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 2.6" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 2.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.5" | 0.1" | 💧 Light watering |
| 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.
Arugula 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.
Arugula Planting Timeline — Iroquois County, IL
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 14 | Mar 14 – Mar 28 |
| Transplant Outdoors | April 18 | Apr 18 – May 2 |
| Direct Sow | April 4 | Apr 4 – Apr 25 |
| Harvest | May 23 | May 23 – Jul 25 |
| Fall Sowing | August 4 | Aug 4 – Aug 18 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.6"/week · Only during dry spells
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
178 days in Iroquois County
Growing Tips for Arugula in Iroquois County
Direct sow Arugula outdoors after April 18 in Iroquois County when soil has warmed and frost danger has passed.
Your generous 178.0-day season in Iroquois County allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.
Common pests for Arugula in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Iroquois County, IL?
Iroquois County is in Zone 5b with an average last frost of April 18. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iroquois County, IL?
Iroquois County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 13.
Your Iroquois County Garden Planner — Free
A 24-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.