When to plant Catnip in St. Clair County, IL
In St. Clair County, Catnip is a single-season spring crop — there's no second fall window. Plant April 9–April 23 for an 60–80-day harvest, finishing well before the November 2 first frost.
When to Plant Catnip in St. Clair County, IL
This month in St. Clair County, Illinois
Each item below is timed to St. Clair County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Pick catnip
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Before August arrives, get these ready
- First harvests: catnip
Catnip is a hardy perennial herb in the mint family known for its effect on cats. It also makes a calming tea and is a useful companion plant that repels some pests.
St. Clair County, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.
At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Catnip during the growing season.
St. Clair County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.3
Drainage
Well Drained
Catnip 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 St. Clair County
How your county's soil matches Catnip's growing requirements.
Soil pH
Your soil pH (6.0–7.3) is within Catnip's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in St. Clair County is excellent for Catnip — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Catnip will thrive.
How to Plant Catnip
Succession Planting Catnip
Sow every 6.9 weeks. Last sowing by Aug 14 to harvest before frost.
Catnip Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Catnip
Catnip 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 | Catnip Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in St. Clair County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Catnip 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.
Catnip Planting Timeline — St. Clair County, IL
Catnip Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
| Harvest | June 11 | Jun 11 – Aug 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 7a
📆 Growing Season
214 days in St. Clair County
Growing Tips for Catnip in St. Clair County
Direct sow Catnip outdoors after April 02 in St. Clair County when soil has warmed and frost danger has passed.
General growing tips
Direct sow or start indoors. Catnip is very easy to grow and can become invasive. Harvest leaves before flowering for tea. Protect young plants from cats.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Catnip in Other Locations
Frequently Asked Questions
When should I plant Catnip in St. Clair County, IL?
St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Clair County, IL?
St. Clair County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 2 and first fall frost is November 2.
When should I plant Catnip in St. Clair County, IL?
In St. Clair County, IL, plant Catnip after the last frost (around April 2) and before the first frost (around November 2). Best results when soil holds above 50°F.
What growing zone is St. Clair County, IL for Catnip?
St. Clair County sits in USDA Zone 7a. Catnip grows reliably in zones 3a through 9b, so it's a good fit here.
Can Catnip grow in St. Clair County's climate?
Yes — Catnip grows well in St. Clair County's temperate climate. St. Clair County averages a 214-day frost-free season, with last frost around April 2 and first frost around November 2.
Your St. Clair County Garden Planner — Free
A 22-page printable planner built for St. Clair County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.