Catnip Quality: 3 Forms, 6-Month Life, 1 Swap a Month

Catnip is a consumable with a real expiry date, and a fair share of what sits on pet shop shelves is already past it. Working dried leaf holds 0.3 to 1 percent nepetalactone by weight, the oil that does the job. A bag left open in a warm room loses about half its punch in 8 to 10 weeks, and by 6 months the toy smells of hay and the cat walks past it. Buy small bags, write the opening date on them, swap 1 toy a month, and keep the reserve sealed in the dark at 4 C or colder.

Response is inherited, not learned: roughly 50 to 70 percent of cats react, kittens under 3 months almost never do, and the switch usually flips between 3 and 6 months. A cat that shows nothing by 8 months is a non-responder, and no stronger product will change that. Skip straight to silvervine, which pulls a reaction in about 60 to 80 percent of cats, including many catnip non-responders.

3 forms, 3 decay rates

Form	Nepetalactone left at 6 months	Dose per session	Swap interval	Cost per month
Whole dried leaf	50 to 60 percent	0.5 to 1 g	4 to 6 weeks	$2 to $4
Ground powder	30 to 40 percent	0.3 to 0.5 g	3 to 4 weeks	$3 to $5
Spray or extract	70 to 80 percent	2 to 3 pumps	8 to 10 weeks	$1 to $3
Leaf plus silvervine mix	45 to 55 percent	0.5 to 1 g	4 to 6 weeks	$4 to $6
Catnip in a sewn toy	20 to 30 percent	1 toy per cat	3 to 4 weeks	$3 to $7

Whole leaf wins on shelf life because the oil sits inside intact plant cells; powder exposes 10 to 100 times more surface to air and gives it up fast. A sewn toy is the worst case: the filling is usually powder or floor sweepings, the fabric breathes, and 3 to 4 weeks is realistic whether or not the label says 12.

The 6-month clock starts at opening

An unopened, foil-sealed bag of whole leaf is good for 12 to 18 months from harvest. The 6-month figure is what you get after the seal breaks, in a screw-top jar, at 20 to 24 C. Three things shorten it further: light, warmth and humidity. At 30 C the loss roughly doubles, and a bag kept in a bathroom at 60 to 70 percent humidity cakes within 4 to 6 weeks and grows mold at the base long before the smell goes.

What a session actually looks like

Sniffing to first reaction takes 2 to 5 seconds, through the vomeronasal organ rather than the nose alone. The response runs 5 to 15 minutes: rolling, cheek rubbing, chin licking, hind-leg kicks, sometimes 20 to 30 seconds of sprinting. Then comes a refractory window of 30 to 60 minutes when the same toy does nothing at all. That gap is why a toy abandoned on the floor looks like a failure at minute 20 and looks like a hit again after dinner. Do not top up during the gap; it wastes herb and teaches the cat to ignore the toy.

Dose per session

For a 4 kg cat, 0.5 to 1 g of whole leaf, about 1/2 to 1 level teaspoon, is a full dose. More does not deepen the reaction, it just raises the dust the cat inhales. Offer 2 to 3 sessions a week, and let the cat walk away: a session forced past 15 minutes turns into over-arousal, with 1 to 2 hard bites at the hand and a cat that hides for 10 minutes after.

1 swap a month, 3 toys in rotation

Keep 3 catnip toys and rotate 1 per month rather than buying 1 new toy a month. Number them 1, 2, 3 with a marker, store 2 sealed in a jar, and put 1 out. On the 1st of the month, seal the one that was out, open the next, and refill the sewn ones with 2 to 3 g of fresh leaf if the fabric is still sound. Rotation costs less than half of constant buying, and it also means the cat meets a genuinely fresh toy every 30 days instead of a dead one every week.

Storage that adds 3 to 4 months

Glass jar with a rubber gasket, filled to 80 percent, not 100 percent, so there is air to buffer humidity swings.
Dark cupboard at 15 to 20 C, or the fridge at 4 C for a bulk bag; the freezer at -18 C is fine for leaf you will not open for 3 months.
No plastic zip bags for longer than 4 weeks; they breathe and they take on the smell of whatever is next to them.
Let a cold jar sit 15 minutes before opening, so condensation does not land on the leaf.

The 3 cm line and the cleaning cycle

Everything a cat can pull off, chew or swallow is measured against 3 cm. A bell, a plastic eye, a pom-pom, a felt mouse tail, a chunk of compressed herb: any piece under 3 cm across is small enough to go down whole and big enough to lodge at the back of the throat, so it does not stay on the toy. Cut it off or sew it down with 4 to 6 stitches of heavy thread, and keep any cord under 15 cm so it cannot become a linear foreign body.

Wash fabric toys every 2 weeks at 40 C in a mesh bag, air dry, and never machine dry, since heat at 60 C plus shrinks the fabric and cooks off what is left of the oil. Wipe hard toys with a damp cloth weekly. Replace the filling every 4 to 6 weeks, the fabric toy every 3 to 6 months, and the whole jar of leaf at 6 months from opening, whichever comes first.

4 reasons to bin it

Throw the toy or the bag out when: the cat no longer reacts and a fresh pinch from a sealed jar still works (so the toy is dead, not the cat), the fabric has a hole that leaks herb, there is any mold, musty or ammonia smell, or any part under 3 cm has worked loose. Mold is the one to act on the same day: a bag that caked at the base has spores through the whole contents, and a cat that inhales a nose full will sneeze for 2 to 3 days.

For cats over 10 that react badly or not at all, the senior alternative covers silvervine and valerian. If the toy itself is the problem rather than the herb, the refresh schedule has the 3-week numbers. To judge how hard a cat will play before you buy, start with the breed quiz.

Frequently asked

How do I tell if my catnip is still any good?

Open a sealed reserve, take a pinch and offer it in a fresh paper bag for 2 minutes. If the cat rolls and rubs within 2 to 5 seconds, the herb is fine and the toy is dead. If both the old toy and the fresh pinch get no reaction, the cat is a non-responder and no product will fix that. Smell alone is a poor test, since a stale bag can still smell strong at 30 percent potency.

Why does 6 months matter if the packet says 12?

The 12 to 18 month figure applies to a foil-sealed bag of whole leaf that has never been opened. Once the seal breaks, whole leaf in a jar at 20 to 24 C runs down to about 50 to 60 percent of its nepetalactone in 6 months, and powder to 30 to 40 percent. Warmth doubles the loss at 30 C, and a humid bathroom cakes the bag in 4 to 6 weeks, well before the smell fades.

Should I give catnip every day?

No. Offer 2 to 3 sessions a week of 5 to 15 minutes each, then let the cat leave. The refractory window of 30 to 60 minutes means a second offer in the same hour does nothing, and pushing a session past 15 minutes produces over-arousal: 1 to 2 hard bites at the hand and a cat that hides for 10 minutes. Rotating 3 toys and swapping 1 per month keeps each session fresh.