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When to Plant Catnip in Rock County, WI

Rock County, Wisconsin Zone 5b May

What to do in May

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

Avg. last frost April 26
Avg. first frost October 13
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Set out catnip seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Rock County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 710 feet, Rock County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Catnip during the growing season.

Rock County, WI (Zone 5b) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13

Rock County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 1
Recommended (50%) ✓ Fits season (37 days to spare)
Transplant: May 3 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (36 days to spare)
Transplant: May 18 🍅 Harvest: Jul 20 – Sep 21

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 Rock County

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

Soil pH

Your soil pH (6.2–7.1) is within Catnip's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Rock 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

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

Succession Planting Catnip

3
successive plantings in your 170-day season

Sow every 6.9 weeks. Last sowing by Jul 25 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
Drought risk

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 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.1" 0" ✅ Rainfall sufficient
Jun 2.2" 3.8" 0" ✅ Rainfall sufficient
Jul 2.2" 3.2" 0" ✅ Rainfall sufficient
Aug 2.2" 3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.6" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Rock 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 ~1,015 GDD — county provides 2,465 GDD Excellent fit

Catnip Planting Timeline — Rock County, WI

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors May 3 May 3 – May 17
Harvest July 5 Jul 5 – Sep 6

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

Month-by-Month Timeline

MonthActivities
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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Rock County

Growing Tips for Catnip in Rock County

Direct sow Catnip outdoors after April 26 in Rock 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 Rock County, WI?

Rock County is in Zone 5b with an average last frost of April 26. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rock County, WI?

Rock County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 13.

🌱

Your Rock County Garden Planner — Free

A 24-page printable planner built for Rock 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.

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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 Rock County, WI. 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.