You can't herd cats, as the saying goes -- and keeping them from pottying in houseplants and flowerbeds, or preventing your house cat from sharpening its claws on the leather sectional poses challenges. With their natural athleticism, indoor cats can go just about anywhere. Fences won't keep strays from using your garden as a free-for-all litter box and few people enjoy hearing amorous yowling from mating cats on the porch after midnight. Some household products can effectively repel cats without harming them.
Scatter mothballs or camphor around your garden, especially in areas cats use for a litter box. Available at hardware stores, these products won't harm your garden, but the strong odour may repel cats.
Sprinkle aromatic essential oils, such as lavender, eucalyptus or peppermint oil to repel cats from forbidden areas. Indoors, soak cotton balls or teabags with the oil and place them wherever you don't want your cat to go.
Use the smell of citrus to your advantage -- many cats dislike the smell. Orange, lemon or grapefruit rinds may repel them. Alternatively, use citrus-smelling essential oils such as lemon grass, citronella or orange.
Spread your old coffee grounds on top of soil outdoors or in houseplants. The coffee grounds are good for the soil, and may repel cats. Some coffee shops give away their grounds to gardeners if you don't drink coffee yourself, or need a lot of grounds.
Use water -- something most cats hate. A well-aimed squirt with a water pistol indoors may convince your cat to stay away from a forbidden area. Outdoors, use a garden hose or sprinkler.
If your indoor cat is pottying outside of the litter box, make sure the box is kept clean and accessible. Inappropriate toilet habits in cats is a common symptom of urinary tract infections; take your cat to the vet if it starts going outside the box.
Don't use anything caustic, such as lemon juice or ammonia, directly on a cat.