When to Plant Catnip in Topeka, Kansas (66621)

Location

Topeka, Kansas

ZIP Code

66621

USDA Zone

Last Frost

Wednesday, April 15, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Wednesday, February 18, 2026

Transplant Outdoors

Wednesday, April 29, 2026

Based on last frost Wednesday, April 15, 2026 · Zone 6b

Pro tip: Start Catnip seeds indoors 8 weeks before your last frost date, then transplant outdoors around Wednesday, April 29, 2026.

🌿 Plant Details

Scientific Name Nepeta cataria

Days to Maturity 90 days

Mature Height 18-36"

Spread 18"

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Low (less than 1 inch/week)

↔️

Spacing

18" apart

🌱

Planting Depth

0.125" deep

Seeds typically germinate in 7-14 days

Ready to Plant Catnip in Topeka?

Get your seeds now so they're ready by Wednesday, February 18, 2026.

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🤝 Good Companions

TomatoPepperSquashPumpkin

🤝

Full Companion Planting Guide for Catnip

See which plants help Catnip thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🪵 Raised Garden Bed 🌍 Vegetable Garden Soil 🛠️ Hand Trowel Set 🚿 Watering Can

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🌾 Seed Saving Guide

🟢 Easy

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Let flower spikes dry completely on the plant. Seeds form in small nutlets inside dried calyxes.

Processing

Strip dried stems over a bowl, rub between fingers to release seeds, winnow lightly.

Seed Viability

Up to 3 years when stored cool, dark, and dry.

Pro Tip

Catnip self-sows freely and can become weedy — deadhead most plants to control spread.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 14 plants of Catnip. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Catnip in Topeka, Kansas? +

In Topeka (Zone 6b), start Catnip seeds indoors around Wednesday, February 18, 2026 and transplant outdoors around Wednesday, April 29, 2026.

What is the last frost date for Topeka, Kansas? +

The average last spring frost date for Topeka, Kansas (ZIP 66621) is around Wednesday, April 15, 2026. This is based on NOAA climate normals for USDA Zone 6b.

How long does Catnip take to grow? +

Catnip typically matures in about 90 days from transplanting. In Topeka, that means you can expect harvest around Wednesday, April 29, 2026 plus 90 days.

Should I start Catnip indoors or direct sow in Kansas? +

Catnip should be started indoors 8 weeks before your last frost date. In Topeka, that means starting around Wednesday, February 18, 2026.

📚 More Catnip Planting Guides

🗺️

Catnip in Kansas

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 6b Catnip Guide

All cities in your zone · Avg dates

→

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Growing Catnip in Zone 6b

Catnip (Nepeta cataria) is a popular garden vegetable. In Topeka, Kansas, which is in USDA Hardiness Zone 6b, you should start seeds indoors around Wednesday, February 18, 2026.

Your average last frost date is Wednesday, April 15, 2026. Plan to transplant your Catnip seedlings outdoors around Wednesday, April 29, 2026, about 2 weeks after your last frost date.