If you have trouble with unwanted cats in your yard, there are several methods you can use to repel them. While there are many commercial products available to deter cats, trying some simple homemade repellents first may save money and be just as effective.
If you notice that visiting cats prefer a particular part of your yard, try sprinkling the area with cayenne pepper, coffee grounds, peppermint oil or eucalyptus oil. Cats will avoid these scents. Cats also do not care for citrus, so you could try placing orange or lemon peels in targeted areas or spraying citronella oil. You may create a boundary around your yard by using these repellents on the perimeter.
Make it more difficult for cats to enter your yard. Fence areas that are open, or string a wire a few inches above the top of fencing so that cats have difficulty walking along it.
Try planting cat-deterring foliage, such as coleus canina or rue. If you have a bird feeder, place cuttings from thorny plants underneath to discourage cats from approaching.
If home remedies do not prove effective, you can try commercial products. There are powders and sprays available, as well as ultrasonic alarms triggered by motion sensors.