Catnip is a hardy perennial in the mint family, famous for the effect it has on cats — most cats roll, rub and purr in it — and useful in the garden as a bee plant and a mild herbal tea. In Zone 10 it grows nearly all year, and one plant is plenty.
Catnip is less invasive than mint, but it is still a vigorous spreader that self-sows freely, so give it room or grow it in a pot. And if you have cats, expect them to find it: protect young plants with a wire cage until they are big enough to survive being rolled on.
Zone 10 at a glance
USDA Zone 10 covers the warmest parts of the United States — South Florida, the southernmost tip of Texas, coastal Southern California and Hawaii. Winters are mild, with average winter lows of 30 to 40°F, and the growing season runs nearly all year, with frost a rare event rather than a season marker.
The average last spring frost in Zone 10 is Jan 15–30, and the average first autumn frost is Dec 15–31 — and frost is rare in most Zone 10 gardens. These are USDA zone averages drawn from NOAA frost records, not exact dates for any one garden — always check your local extension service and the forecast before planting tender crops outside.
| Detail | Zone 10 guidance |
|---|---|
| Average winter low | 30 to 40°F |
| Average last spring frost | Jan 15–30 (frost rare; average/range) |
| Average first autumn frost | Dec 15–31 (frost rare; average/range) |
| Days to germination | 7–14 days |
| Days to maturity | 70–90 days |
| Sowing | both |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 12–18 inches |
| Water needs | low |
| Cold tolerance | hardy |
When to plant catnip in Zone 10
Sow or plant catnip in Zone 10 from October through April, from seed, nursery plants or divisions. Seed takes 7–14 days to germinate and plants mature in 70–90 days, so an autumn sowing is ready by mid-winter. The average last spring frost is Jan 15–30 and the average first autumn frost is Dec 15–31, and frost is rare, so there is no frost deadline — the cool months simply give young plants the easiest start. An established plant survives Zone 10 summers, though it may look scruffy in the hottest weeks and benefits from a hard cut back.
The planting calendar hub gives the Zone 10 picture month by month, and the seed starting calculator can help you work out exact sowing dates.
Starting catnip in Zone 10
Start catnip from seed indoors or direct-sow into prepared beds, or divide an established clump in autumn. Seed germinates in 7–14 days; chill seed in the fridge for a few days first if germination is poor. Space plants 12–18 inches apart in full sun and soil that drains freely, and water young plants until established. Catnip grows well in pots, which keeps it contained and makes it easy to move out of reach of cats when it is young. Protect new plants with a wire cloche until they are sturdy — cats will flatten a small plant in minutes.
Soil, spacing, sun and water
Catnip needs full sun in Zone 10 — in the hottest months a little afternoon shade keeps leaves tender and prevents scorch, but too much shade weakens flavour and growth. It grows best in soil with a pH of 6.0–7.0. Catnip is not fussy, growing well in ordinary garden soil with a pH of 6.0–7.0. It prefers soil that drains freely and does not need rich feeding — lean soil gives stronger-scented leaves. Space plants 12–18 inches apart so air can move between them; crowded plants stay damp and invite disease in Zone 10 humidity. Water needs are low: water deeply but infrequently once established, and let the soil dry between waterings — wet feet are the fastest way to lose this plant in Zone 10. A raised bed or a pot with drainage holes is often the easiest way to get the drainage right, and the soil volume calculator helps you work out how much mix a bed or container needs.
Companion planting
Good companions for catnip include tomatoes, peppers, marigolds, cabbage. Catnip grows well near tomatoes, peppers and cabbage, and its strong scent is said to deter aphids, flea beetles and other pests. Its flowers attract bees in large numbers. Keep it contained, since it spreads and self-sows freely. The October guide for Zone 10 in October shows what else is going in at the same time.
Our guide to when to plant chives in Zone 10 shows how to time a second crop alongside it. For comparison with a cooler zone, see when to plant catnip in Zone 9.
Pests and problems
The common pests to watch for with catnip are aphids, spider mites, whiteflies. Aphids may gather on soft growth — wash them off with water. Spider mites appear in hot, dry spells, and whiteflies are occasional. Catnip's biggest pest in Zone 10 is often the neighbourhood cats — protect young plants with wire until they are big enough to take the attention. Check the undersides of leaves weekly — most Zone 10 pest problems are small when caught early and much harder once they spread. Avoid spraying broad insecticides on herbs you plan to eat; a strong jet of water, hand-picking and encouraging ladybirds and other beneficial insects will deal with most outbreaks.
Harvest and storage
Start picking catnip once plants are established, about 70–90 days after planting, and pick little and often. Cut stem tips in the morning, and cut whole stems just before flowering for the strongest effect on cats — the active compound is strongest in the leaves at that stage. Use leaves fresh for tea or for cats, or dry small bunches in a warm, airy spot and store them in a sealed jar; dried catnip keeps its potency for months. Cut plants back hard after flowering for a fresh flush of growth.
Frequently asked questions
When should I plant catnip in Zone 10?
Sow or plant from October through April. Seed takes 7–14 days to germinate and plants mature in 70–90 days.
Will catnip take over my garden?
It spreads and self-sows freely, though it is less aggressive than mint. Grow it in a pot or give it room, and deadhead if you do not want seedlings.
How do I protect catnip from cats?
Cover young plants with a wire cage or cloche until they are big and sturdy. Mature plants can take the attention; small ones get flattened.
Do all cats react to catnip?
No — most cats do, but some do not react at all. The response is inherited, and kittens under a few months old usually ignore it.