When to plant Catnip in Harrison County, IA
Plant Catnip in Harrison County, between May 1 and May 15 — the only viable window. Zone 5b's short season (169 frost-free days) rules out a fall crop.
When to Plant Catnip in Harrison County, IA
Harrison County, Iowa gardeners: here's your August plan
Each item below is timed to Harrison County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.
-
Collect catnip at their peak
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Before September 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.
Harrison County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 10, giving you a growing season of approximately 169 days.
At an elevation of 1,345 feet, Harrison County receives approximately 35.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Catnip to ensure they mature before fall.
Harrison County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.2
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 Harrison County
How your county's soil matches Catnip's growing requirements.
Soil pH
Your soil pH (5.8–7.2) overlaps with Catnip's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Harrison County is excellent for Catnip — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Catnip will thrive.
How to Plant Catnip
Succession Planting Catnip
Sow every 6.9 weeks. Last sowing by Jul 22 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Harrison 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 — Harrison County, IA
Catnip Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Harvest | July 3 | Jul 3 – Sep 4 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
169 days in Harrison County
Growing Tips for Catnip in Harrison County
Direct sow Catnip outdoors after April 24 in Harrison 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 Harrison County, IA?
Harrison County is in Zone 5b with an average last frost of April 24. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.
What planting zone is Harrison County, IA?
Harrison County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 10.
When should I plant Catnip in Harrison County, IA?
In Harrison County, IA, plant Catnip after the last frost (around April 24) and before the first frost (around October 10). Best results when soil holds above 50°F.
What growing zone is Harrison County, IA for Catnip?
Harrison County sits in USDA Zone 5b. Catnip grows reliably in zones 3a through 9b, so it's a good fit here.
Can Catnip grow in Harrison County's climate?
Yes — Catnip grows well in Harrison County's temperate climate. Harrison County averages a 169-day frost-free season, with last frost around April 24 and first frost around October 10.
Your Harrison County Garden Planner — Free
A 22-page printable planner built for Harrison 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.