Every day I have to go out and clean up after them. They dig and make a mess for me. Is there any deterrent like a spray that I could put on the ground to keep them away.?

i hardly ever got cats on my garden because i had a cat before i had to have him put to sleep,they never came near there are plants but they dont stop cats even though were told it stops them if you go to the pet shop they may recommend something for you the thing is cats just wonder everywere they wont do there bis on their own garden
hope you get sorted

Hang mothballs in a nylon stocking around the garden so they don't touch the ground. Replace when the rain eventually melts them away.

But really, why not just toss a little more dirt on the poop and let it be? The strays around here all use my flower garden in front and it's helped the plants grow like a Brazillian jungle out there! It's great fertilizer!