When to Plant Parsley in Cass County, IL
Parsley is a biennial herb available in flat-leaf (Italian) and curly varieties. It is a nutritional powerhouse rich in vitamins C and K and adds fresh flavor to countless dishes.
Cass County, Illinois is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 16, giving you a growing season of approximately 184 days.
At an elevation of 703 feet, Cass County receives approximately 31.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Parsley to ensure they mature before fall.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
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 Cass County
How your county's soil matches Parsley's growing requirements.
Soil pH
Your soil pH (6.0–7.2) overlaps with Parsley's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Cass County is excellent for Parsley — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Parsley.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Parsley.
How to Plant Parsley
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Parsley
Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.
For a dedicated fall crop, sow by Aug 07.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Parsley
Parsley 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 | Parsley Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.6" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cass County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Parsley 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.
Parsley Planting Timeline — Cass County, IL
Parsley Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 11 | Mar 11 – Mar 25 |
| Transplant Outdoors | April 8 | Apr 8 – Apr 22 |
| Direct Sow | April 1 | Apr 1 – Apr 22 |
| Harvest | June 10 | Jun 10 – Aug 12 |
| Fall Sowing | August 7 | Aug 7 – Aug 21 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.6"/week · Only during dry spells
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
184 days in Cass County
Growing Tips for Parsley in Cass County
Direct sow Parsley outdoors after April 15 in Cass County when soil has warmed and frost danger has passed.
Common pests for Parsley in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Soak seeds overnight as germination is slow. Harvest outer stems first to keep plants productive. Parsley attracts swallowtail butterflies.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Parsley in Other Locations
Frequently Asked Questions
When should I plant Parsley in Cass County, IL?
Cass County is in Zone 5b with an average last frost of April 15. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, IL?
Cass County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 15 and first fall frost is October 16.
Plan Your Garden with Confidence
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