Catnip is the herb your cat already knows about: the leaves contain nepetalactone, which sends most cats into a happy frenzy, and the plant itself is a tough, mint-family perennial that asks for almost nothing. Starting it from seed indoors is easy, and a packet goes a long way — one plant is usually plenty.
Catnip seed germinates readily with a gentle indoor start, and the seedlings are sturdy enough to forgive a beginner's mistakes. This guide covers the simple sowing method, the timing that gets plants established before summer, and the one practical warning every cat owner needs: protect young plants from the cats until they are big enough to survive the attention. Catnip can be started indoors or direct-sown — its sowing method is listed as "both" — and indoor sowing is the better choice if you want an earlier start, more even germination, or plants ready for the first warm weeks of the season. This crop is in the Lamiaceae family, needs full sun, and takes 70–90 days to reach maturity, so the timing below is built around those facts, not guesswork.
Catnip at a glance
| Growing factor | What catnip need |
|---|---|
| Days to germination | 7–14 |
| Sowing method | both |
| Days to maturity | 70–90 |
| Soil pH | 6.0–7.0 |
| Spacing | 12–18 inches |
| Sun | full sun |
| Cold tolerance | hardy |
When to start catnip seeds indoors
In Zones 3–5, start indoors 6–8 weeks before your last frost. In Zones 6–8, 4–6 weeks is enough, and in Zones 9–10 you can sow indoors in late winter or direct-sow once the soil warms. In frost-free Zones 11–13, sow in the cooler months — catnip dislikes intense heat. Check your local extension service for frost dates, or use our frost-date calculator and seed-starting calculator.
As a rule, work backwards from your last frost: sow indoors 6–8 weeks before it if you are starting indoors at all, and check the seed packet against the germination time of 7–14 days. Our seed-starting calculator does the backwards maths for you, and the germination-time calculator helps you plan around that 7–14-day window. If you are unsure of your zone, the hardiness-zone finder will confirm it.
What you need
a seed tray or small pots, seed-starting mix, a spray bottle, a clear lid or cling film, a grow light or bright windowsill, labels, and — if you have cats — a tray cover or a room with a door. Cats will roll on seedlings given half a chance.
You will also want a spray bottle or a watering can with a fine rose, and a notebook to record the sowing date — germination takes 7–14 days, and it is easy to forget when you sowed.
Step by step: starting catnip seeds indoors
- Fill your containers. Fill trays or pots with fresh, damp seed-starting mix — not garden soil, which is too heavy and can carry disease. Press it down lightly and level the surface.
- Sow the seed. Sow catnip seed shallowly in damp seed-starting mix — a light covering of mix is fine — and keep the tray warm and bright. Germination takes 7–14 days and is usually even. Thin to one seedling per cell once they have two true leaves. Catnip seed benefits from an overnight soak in warm water before sowing if your seed is more than a year old.
- Cover and label. Cover the tray with a clear lid or cling film to hold humidity, and label it with the crop and the date. Put it somewhere warm and bright, out of direct sun until seeds sprout.
- Wait for germination. Germination takes 7–14 days. Check the tray daily, mist the surface if it dries, and be patient — uneven germination is normal, especially for slow crops. Our germination-time calculator helps you track the window.
- Remove the cover. As soon as seedlings emerge, take the lid off. Good airflow from this point on is what prevents damping off.
- Give them light. Move the tray under a grow light or to your brightest window immediately — seedlings stretch within a day or two if the light is weak.
- Thin and pot on. Thin to one seedling per cell once they have two true leaves, snipping the extras rather than pulling them. Pot on into larger pots when roots show at the drainage holes, keeping the seedlings at the same depth.
- Feed lightly. Once seedlings have two sets of true leaves, feed with a half-strength liquid feed every week or two. Do not overfeed — soft, overfed seedlings are more likely to damp off and less likely to harden well.
Light for seedlings
Give catnip seedlings 14–16 hours of bright light a day. They tolerate a windowsill better than most herbs, but a grow light a few inches above the leaves still gives sturdier plants. Turn the tray daily if you use a window.
Watering seedlings
Catnip has low water needs once established, but seedlings like steady moisture. Water from below and let the surface dry slightly between waterings. Soggy mix invites damping off; bone-dry mix stalls growth. Aim for damp, not wet. Our watering calculator can help you work out how much water your seedlings need as they grow.
Hardening off
Catnip is hardy, so hardening off is straightforward: 7–10 days of increasing outdoor time, starting in sheltered shade and building to full sun. It can handle a light frost once hardened, but give young plants a few days outdoors first.
Transplanting outdoors
Plant out after the last frost, in full sun and well-drained soil. Space plants 12–18 inches apart — catnip bushes out quickly. Our plant-spacing calculator works out the layout. Protect young plants from cats with a wire cloche or a ring of twiggy branches until they are established; a mature plant can take the attention, a seedling cannot. For the full picture — soil, feeding, pests and harvest — see our complete growing catnip guide.
Common problems and fixes
| Problem | Fix |
|---|---|
| Cats destroy the seedlings | The classic catnip problem. Keep trays behind a closed door or under a cover indoors, and protect transplants with a cloche until they are big and bushy. |
| Leggy seedlings | Not enough light. Move the grow light closer and give 14–16 hours a day. |
| Damping off | Stems collapse at soil level. The mix was too wet. Water from below and remove the lid once seeds sprout. |
| Seedlings stall | Usually cold or a mix that stays wet. Keep the tray warm and let the surface dry between waterings. |
Cats destroy the seedlings
The classic catnip problem. Keep trays behind a closed door or under a cover indoors, and protect transplants with a cloche until they are big and bushy.
Leggy seedlings
Not enough light. Move the grow light closer and give 14–16 hours a day.
Damping off
Stems collapse at soil level. The mix was too wet. Water from below and remove the lid once seeds sprout.
Good companions for catnip include tomatoes, peppers, marigolds, cabbage. Watch out for aphids, spider mites, whiteflies — check young plants regularly, and deal with pests early while plants are small. Our pest-identifier helper can help you work out what you are looking at.
Frequently asked questions
How long do catnip seeds take to germinate?
7–14 days in warm, damp conditions. Germination is usually quick and even.
Can I direct sow catnip?
Yes, catnip can be direct-sown once the soil warms, but indoor sowing gives an earlier start and lets you protect the seedlings from cats.
How far apart should catnip plants be?
12–18 inches apart in full sun and well-drained soil.
Will catnip come back every year?
Yes, it is a hardy perennial. Cut it back after flowering and it regrows from the roots.
When can I harvest catnip?
About 70–90 days from sowing. Pick the leaves before the plant flowers, when the oils are strongest, and dry them for your cat's toys.