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When to Plant Catnip in Clark County, MO

Clark County, Missouri Zone 6a May

May in the garden — Clark County, Missouri

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Clark County, Missouri.

Avg. last frost April 16
Avg. first frost October 18
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
Get ahead of June
  • First harvests: catnip

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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.

Clark County, Missouri is in USDA Zone 6a. The average last spring frost is April 16 and the first fall frost is October 18, giving you a growing season of approximately 185 days.

At an elevation of 833 feet, Clark County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Catnip during the growing season.

Clark County, MO (Zone 6a) Moderate season
185 days
Last Spring Frost April 16
185 growing days
First Fall Frost October 18
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Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 21
Recommended (50%) ✓ Fits season (52 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Aug 27
Safe Start (90%) ✓ Fits season (48 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Sep 12

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 Clark County

How your county's soil matches Catnip's growing requirements.

Soil pH

Your soil pH (5.6–6.6) overlaps with Catnip's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Clark County is excellent for Catnip — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Catnip.

How to Plant Catnip

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Catnip

3
successive plantings in your 185-day season

Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 4.1" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.6" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clark 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 needs ~1,068 GDD — county provides 2,821 GDD Excellent fit

Catnip Planting Timeline — Clark County, MO

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors April 23 Apr 23 – May 7
Harvest June 25 Jun 25 – Aug 27

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June Harvest
July Harvest
August Harvest
September
October
November
December
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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 6a

📆 Growing Season

185 days in Clark County

Growing Tips for Catnip in Clark County

Direct sow Catnip outdoors after April 16 in Clark 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 →

Frequently Asked Questions

When should I plant Catnip in Clark County, MO?

Clark County is in Zone 6a with an average last frost of April 16. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, MO?

Clark County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 16 and first fall frost is October 18.

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Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clark County, MO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.