If neighbourhood cats are using your flower beds for a toilet, consider natural, instinctual feline behaviour when devising a plan to keep them out. Loose soil beckons cats that are looking for a suitable place to relieve themselves, and it just so happens that your gardening areas fit the bill precisely. Approach this matter sensibly, and try tactics that are kitty-kind. You're likely to find that cats can indeed be reasonable creatures that will go elsewhere when you make your garden less attractive to them.
Cut squares or strips of bird netting to cover open areas in your flower beds. This will prevent them from digging in the loose soil. If they can't dig, they won't go. Bird netting is inexpensive, available in any garden centre and cuts easily with scissors.
Use wire cutters to make sections of carpenter's cloth or chicken wire to cover loose gardening soil if you don't care to use bird netting. It's heavier and stays put effectively.
Poke the handles of plastic forks into the soil so that the tines are facing up. Space them about 6 inches apart. Felines won't be able to dig holes or dig up the forks.
Bury some pine cones about halfway in flower bed soil. Space them about 6 inches apart. Cats do not like to walk on pine cones or other prickly things. Your neighbours who own pine trees probably won't mind sharing their fallen cones.
Layer some bulky decorative mulch such as rocks or stones wherever possible. Heavy rocks or stones are much more challenging than dirt when it comes to digging a toilet, and cats will choose an easier place to use as a toilet.
Use repellents. Cats don't like the smell of coffee, so scatter your used coffee grinds over loose soil. They aren't fond of citrus fruits, so cut your orange peels and lemon, lime or grapefruit rinds into small pieces and broadcast them into flower beds. Purchase commercial animal repellent granules from your local garden centre and apply them as prescribed by the packaging instructions. One of these tactics or any combination of them may be perfect for your situation.
Plant some rue (Ruta graveolens) among your flowers. This herb is easy to grow, and cats find the odour of this attractive perennial repugnant. Rue tolerates poor soils and will grace your summer gardens with yellow bloom clusters.
Hang your bird feeder high enough so that cats can't reach it. They may be venturing onto your property in hopes of catching a unsuspecting bird while it's dining. If cats can't reach the feeder, they might go hunting elsewhere for easy prey.
Bring your own pet's food inside at night to avoid inviting stray cats to dinner.