Catnip grows vigorously when you sow seeds directly in the garden after soil warms. Knowing exactly When To Plant Catnip is the key to a lush, happy patch that your feline friends will love. This guide covers everything from seed starting to transplanting, so you get it right the first time.
Catnip (Nepeta cataria) is a hardy perennial herb from the mint family. It’s super easy to grow, but timing matters. Plant too early and cold soil rots the seeds. Plant too late and you miss the best growing weather.
Let’s break down the perfect planting window for your zone, plus tips for indoor starts and direct sowing.
When To Plant Catnip
The short answer: plant catnip seeds outdoors in spring, after the last frost date, when soil temperatures reach at least 60°F (15°C). For most gardeners, that’s 2–4 weeks after the final frost. If you’re starting indoors, begin seeds 6–8 weeks before your last expected frost.
But there’s more to it than just a date on the calendar. Soil temperature, sunlight, and your local climate all play a role. Below I’ll walk you through the exact steps.
Why Timing Matters For Catnip
Catnip seeds need warmth to germinate. Cold, wet soil causes them to rot or grow slowly. If you plant too early, you might get patchy germination. Too late, and the plants won’t have enough time to establish before summer heat or fall frost.
Catnip also self-sows easily. Once you have a few plants, you’ll likely see volunteers popping up next spring. That’s a good sign you’ve found the right timing.
Check Your Hardiness Zone
Catnip grows in USDA zones 3 through 9. But the planting window shifts depending on where you live. Here’s a quick guide:
- Zones 3–4: Plant seeds outdoors in late May or early June. Start indoors in mid-April.
- Zones 5–6: Direct sow in mid-to-late April. Indoor start in early March.
- Zones 7–8: Plant outdoors in March or early April. Indoor start in February.
- Zone 9: Sow in February or March. You can also plant in fall for a winter crop.
Always check your local frost dates. A quick online search for “last frost date [your city]” gives you a reliable target.
Soil Temperature Is The Real Key
Forget the calendar for a moment. The most accurate way to know When To Plant Catnip is to measure soil temperature. Use a simple soil thermometer. Insert it 2 inches deep in the garden bed. Wait until it reads at least 60°F (15°C) for three consecutive mornings.
Catnip seeds germinate best between 65°F and 75°F (18–24°C). If your soil is cooler, germination is slow and uneven. Warmer than 85°F (29°C) can also reduce germination rates.
If you don’t have a thermometer, watch for signs of spring: dandelions blooming, lilacs leafing out, or soil that crumbles easily in your hand instead of forming mud.
How To Plant Catnip Seeds Outdoors
Direct sowing is the easiest method. Catnip doesn’t like root disturbance, so planting seeds where they’ll grow saves you trouble. Here’s a step-by-step process.
Step 1: Prepare The Soil
Choose a sunny spot with well-draining soil. Catnip tolerates poor soil but thrives in loamy, slightly sandy ground. Remove weeds and rocks. Rake the surface smooth.
If your soil is heavy clay, mix in some compost or sand to improve drainage. Catnip hates wet feet.
Step 2: Sow The Seeds
Scatter seeds thinly over the prepared bed. Cover them with about 1/8 inch of fine soil or vermiculite. Catnip seeds need light to germinate, so don’t bury them deep. Press the soil down gently so seeds make contact.
Space seeds about 12 inches apart if you want mature plants. You can always thin later.
Step 3: Water Gently
Use a fine mist or a watering can with a rose attachment. Keep the soil consistently moist but not soggy. Seeds germinate in 7–14 days, depending on temperature.
If you get a heavy rain, check that the seeds aren’t washed away. A light layer of straw or row cover can protect them.
Step 4: Thin Seedlings
Once seedlings have two sets of true leaves, thin them to one plant every 12–18 inches. Snip extras at soil level instead of pulling them up, so you don’t disturb the roots of the ones you keep.
Transplant thinned seedlings to another spot if you want more plants. Just be gentle with the roots.
Starting Catnip Seeds Indoors
If you have a short growing season or want a head start, indoor sowing works great. You’ll need a sunny windowsill or grow lights.
When To Start Indoors
Count back 6–8 weeks from your last frost date. For example, if your last frost is May 1, start seeds around March 15. This gives seedlings enough time to develop before moving outside.
Materials You’ll Need
- Seed starting trays or small pots with drainage holes
- Seed starting mix (light and sterile)
- Spray bottle for watering
- Plastic dome or bag to create humidity
- Grow lights or a bright south-facing window
Sowing Steps Indoors
- Fill trays with moistened seed starting mix.
- Sow 2–3 seeds per cell, 1/8 inch deep.
- Cover lightly with mix or vermiculite.
- Mist the surface gently.
- Cover with a humidity dome or plastic wrap.
- Place in a warm spot (65–75°F).
- Remove cover once seeds sprout (7–14 days).
- Move trays under lights or to a sunny window.
- Keep soil moist but not waterlogged.
Hardening Off Seedlings
About a week before transplanting outdoors, start hardening off your seedlings. Set them outside for a few hours each day in a sheltered spot. Gradually increase time and sun exposure over 5–7 days. This prevents shock and sunburn.
Transplant after the last frost date, spacing plants 18 inches apart. Water well after planting.
Planting Catnip In Containers
Catnip grows well in pots. This is great if you want to control spreading or keep it on a patio. Container planting follows the same timing rules as garden planting.
Best Time For Container Planting
You can plant catnip in containers as soon as the weather warms in spring. If you’re using a pot indoors, you can start any time. But for outdoor containers, wait until after your last frost date.
Use a pot at least 8 inches deep with drainage holes. Fill with well-draining potting mix. Catnip in containers needs more frequent watering than garden plants, especially in summer.
Overwintering Potted Catnip
In cold zones, move containers to a sheltered spot or garage before hard frost. Catnip is perennial but roots can freeze in pots. Mulch around the pot or wrap it in bubble wrap for insulation.
You can also bring the pot indoors to a cool, bright room. Water sparingly through winter.
When To Plant Catnip In Fall
In mild climates (zones 8–9), you can plant catnip in fall for a winter harvest. Sow seeds in September or October, about 6–8 weeks before the first expected frost. Plants will grow slowly through winter and take off in spring.
In colder zones, fall planting isn’t recommended. Seeds won’t germinate in cold soil, and young plants may not survive winter. Stick to spring planting.
Catnip Companion Planting Tips
Catnip is a great companion for many vegetables. It repels aphids, flea beetles, and squash bugs. Plant it near brassicas, cucumbers, or squash. But keep it away from other mint family plants to avoid cross-pollination or crowding.
Catnip also attracts beneficial insects like bees and parasitic wasps. Just be aware it can spread aggressively. Some gardeners contain it in pots or prune flowers before they go to seed.
Common Mistakes When Planting Catnip
Even experienced gardeners make errors. Here are the most common ones and how to avoid them.
- Planting too deep: Catnip seeds need light to germinate. Cover them very lightly.
- Overwatering: Soggy soil causes root rot. Let the top inch dry out between waterings.
- Planting in shade: Catnip needs full sun (6+ hours daily) for best growth. Shade makes it leggy.
- Ignoring frost dates: Even a light frost can kill young seedlings. Wait until the danger has passed.
- Not thinning: Crowded plants compete for nutrients and get spindly. Thin early.
How To Harvest Catnip
You can start harvesting leaves once the plant is at least 6 inches tall. Pick leaves in the morning after dew dries. Cut stems just above a leaf node to encourage bushier growth.
For the strongest catnip effect on cats, harvest just before flowers open. The essential oil (nepetalactone) is highest at this stage. Dry leaves in a dark, airy place for a few days. Store in an airtight jar.
You can also harvest flowers for tea or dried arrangements. Just know that once flowers appear, leaf potency drops.
Frequently Asked Questions About Catnip Planting
Can I Plant Catnip Seeds Directly In The Ground?
Yes, direct sowing is the easiest method. Wait until soil temperature is at least 60°F and all frost danger has passed. Scatter seeds on the surface and cover lightly.
How Long Does Catnip Take To Grow From Seed?
Catnip seeds germinate in 7–14 days under ideal conditions. Plants reach full size in about 3–4 months. You can start harvesting leaves after 6–8 weeks.
Does Catnip Come Back Every Year?
Yes, catnip is a perennial in zones 3–9. It dies back in winter and regrows from the roots in spring. It also self-seeds readily, so you may get new plants each year.
What Month Is Best To Plant Catnip?
For most zones, April or May is best for outdoor planting. Check your local last frost date. In warmer zones, you can also plant in September for a fall crop.
Can I Plant Catnip In Partial Shade?
Catnip prefers full sun but tolerates light shade. However, plants will be less bushy and produce fewer leaves. For the best harvest, give it at least 6 hours of direct sunlight daily.
Final Thoughts On Catnip Planting Timing
Getting the timing right for catnip is simple once you understand soil temperature and frost dates. Start seeds indoors for an early jump, or sow directly in the garden after the soil warms. Either way, you’ll have a vigorous patch that keeps your cats entertained and your garden buzzing with beneficial insects.
Remember to water consistently, thin seedlings, and harvest regularly for the best results. Catnip is forgiving, so don’t stress if you’re a few days off. Just adjust next season.
Now you know exactly When To Plant Catnip. Grab your seeds, check the forecast, and get growing. Your feline friends will thank you.