The first line of defence is to ensure that your yard boundaries are secure. Any gaps in your fence should be blocked to deny low level access. But cats can jump so fix a taut wire or string some six inches above the top of your fence to deter this approach.
Once inside your garden many people say that the best cat repellent is a dog who will soon see off any feline invader. If you are not a dog lover then you will have to resort to more passive methods. Since cats like to lie on freshly dug soil you should lay mulch on your borders so that no bare soil is left exposed. Seed beds should be covered with wire netting or twigs arranged as a barrier.
Young trees should have plastic guards fitted around their trunks to protect them against use as a scratching pole.
Your garden pond should be covered with netting to keep your fish safe.
Cats are generally known to dislike water so a well aimed bucketful or a squirt with the hose will certainly make an intruder run. After one or two dousings it may learn the lesson and stay away.
To protect plants and borders both mothballs and citrus are said to be effective deterrents. Place the mothballs, orange peel or lemon rind in the borders. Alternatively spray cloths with orange scented air freshener and place the cloths around the plants you wish to protect. Other known cat repellents are cayenne pepper, coffee grounds, pipe tobacco, lavender oil, lemon grass oil, citronella oil, eucalyptus oil and mustard oil.
Certain herbs are said to deter cats. In particular rue but not catmint which has the opposite effect. Coleus canina is another plant which is marketed by one merchant as a cat repellent.
The broadcaster Jerry Baker has suggested treating your yard with a tonic made from chewing tobacco, urine, birth control pills, mouthwash, molasses, detergent and beer. A smallholder has reported success using dried rabbit blood but you may feel that the ingredients listed in the previous paragraph should be tried first.
If you visit your local garden center or hardware store you will find several cat repellent products on sale. These range from electric water sprinklers and ultrasonic devices to sprays and granules.
Motion activated sprinklers act in the same way as a burglar alarm using an infra red detector. When the cat enters the area covered by the detector the sprinkler shoots out a jet of water to scare the animal away. It is claimed that, after one or two encounters with the jet, the cat will learn to avoid the area.
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