Naturally cats from your neigborhood often treat your garden as part of their territory and unfortunately this includes occasionally pooping in your garden. Luckily there are several natural ways and products you can buy to help keep them away from you lawn.
Products range from granules and lion manure that you spread on your lawn to ultrasonic and water sprayer repellers that keep cats away automatically. Granules ofcourse need to be re-applied every week or so whereas ultrasonic repellers and automatic water sprayers will offer a more permanent solution.
Keep in mind the size of the area you want to discourage the cats from using. For large lawns ultrasonic repellers are ideal - but bare in mind that you may need more than one to cover your whole garden. If you just have a small front lawn or flower bed then granules or lion manure would be a quick and easy solution. Ultrasonic repellers though initially more expensive are in the long run cheaper than using granules which only last a few weeks before naturally degrading.
Natural cat deterrents range from plants, to creating surfaces that cats don't like to walk across. Cats can be detered by the scents of lavender plants, so planting a few in your favorite flower bed may keep them away from the area. Other plants to try are the herb Rue and the Curry plant.
Citrus smells also deter cats so another option is to use lime, lemon or orange peel on your flower beds. Other natural solutions include adding shiny objects such as foil to your flower bed, if caught in a breeze the shimmering may put them off the area.
Adding spikes to your fences can deter cats from perching on them and coming into your garden in the first place. Be sure to cover your whole fence length though as cunning cats will always find a gap if it's there. Chicken wire can be used to cover gaps under and around fences to make your defences more water tight.