How do I keep the neighborhood cats from using my flower planter as a litter box? The spray on stuff doesn't

Sprinkle some powdered cayenne pepper on the soil of the planter. I use it in my garden at home, as well as my planters, and it keeps cats, dogs, squirrles, and rabbits out.

Don't bother with the spray trash. My puppies ran because of the sound but once I walked away they were right up0 there sniffing & marking. GOOD STUFF!!! Got any friends who hunt or know wild animals. The fur of a predator ie bobcat, mt. lion should repel a smart cat. Rags or cotton w/ammonia

Put some mesh or chicken wire over the top of the dirt, or some landscaping stones. Cats can't dig through it and will go elsewhere.

Plant some lemon-scented thyme in your flower planter, cats don't like the lemon smell. Or sprinkle lemon juice around it,you could also use lemon peels too.

I don't know how big your planters are, but you could add mulch to them. Cats like loose dirt/litter etc. The heavier mulch with the bigger wood chips should keep them out. Burying moth balls under the chips should REALLY keep them out!

you can make solution of half a cup of ammonia to three and a half cups of water then spray the area every other morning.

Try spreading moth balls around your flower beds. My neighbors tried this and it worked really fast. Good luck!

MOTHBALLS! They also sell a product that you can spray around your house, I think its called stay off.

Spinkle pepper in it and that will be the last time you see a cat near it!